I don't know if anyone had mentioned it, but after walking past my neighbor's driveway I completely forgot about the Dodge Neon. Okay, they're really not good to look at, and sure, not all of them were built too well, but hot-damn are they cheap! You can get ahold of a used 2005 Neon SRT-4 in the $15K range, although I'm uncertain of the mileage and what kind of abuse the car may/may not have been subject to. I know they are a favorite at autoX events, and the previous Neon R/T and ACRs were favorites in SCCA racing, so they may be worth a look as well.
I personally would be impartial to the earlier ACR and R/T models myself, the last of the ACRs being outstandingly cheap. According to Edmunds, you could get your hands on a 2002 ACR for about five grand, but much like the SRT-4, God only knows what its been through.
I've never seen a Neon ACR, but honestly, a Neon is really the last choice. I can't imagine there being a large aftermarket base for that car unless it involves ricey kits. So, unforunately, I'd have to say no, unless it's I either find a SRT-4, or find a large abundance of performance parts for it.
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Interesting idea: What about the Chrysler Crossfire? I had the "pleasure" of driving one shortly after their launch, and while it certainly was a Mercedes SLK underneath, it wasn't too bad of a car. I had it up to 110 MPH out on a back-road, and while going through some of the river-runs, the overall drive seemed pretty decent. My only complaint was the lack of space in the car, but me being about 6" tall, its a bit understandable. You should be able to get a 2004 model for about $15K these days, although a local Chrysler dealer may just sell you a brand-new one for that price because they want to get rid of them. They're not bad cars, they just weren't given enough love from the start...
The Crossfire is an interesting choice, but I imagine they'll be costing as much as to insure as the S2K. But like the Neon, I'd probably want to go for either a model right under the SRT-8 or just go for the SRT.
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Did anyone mention the Pontiac GTO?
The Corvette parts make modifications easy, the chassis was already well-sorted out of the factory, and its a pleasure to drive (as I understand it) both in town and on the track. I've seen 2004 models going for about $15K-ish without too many miles on the clock, but you are down 50 BHP to the 2005 and 2006 models.
I'll def. look into them, but I don't see them being likely. I imagine many are around 70,000 miles, and it's what, 3-4 years old now? I'd recognize that has an engine that's probably seen a lot of time on the road at 16,000 miles per year on average. I, honestly, don't even put that much on 1 car.
^ So far, I think that is the only drawback on that magnifacent roadster. Other than that, the car is already very good if not excellent right out of the box. It is still the pinnacle of total driving experience in my book, even after driving the 996 GT3 and an [E39] M5.

👍
But like those 2 examples, it's just costly. The only way I could afford to really keep an S2K is to lease one after the 330, and that'd have to be the new CR.
However, the Honda dealers here refuse to lease me one for a reasonable price just because it's the CR and other factors. Plus, I'm pretty much set on the 335i.
-> If its still too pricey, might as well get the 1st or 2nd gen MX-5 Miata or an MR-S/MR-2 Spyder. They're light, reliable, and tons of aftermarket goodies to suit your wants and needs.
I've been looking at them since they started getting a lot of mentions, but I can't believe the MR-2 Spyder would a better car than the first 2 generations.
It would depend on who is running the event. I've mostly seen lapping groups based on drivetrain, then maybe split those up into skill levels. Also for racing series, many organizations base their groupings by SCCA standards, so that's where you should check out things like car classes.
Also, you won't be racing right away. Check you local track where you will do the most tracking and find out who runs sessions there, and find out how they operate. Go down one day to spectate and talk to the organizers and drivers to see what they think of the whole deal. That might help you chose a car.
Then if you want to step it up and race, take a look at the closest series and what cars are running, how they divide up things etc etc.
So, rules will play a favor. Huh. Well, I'll look into that as well, then.
That black Legacy is serious business...I like it. I think a Subaru would probably be a really good choice since they are cheap, AWD, and can be tuned to annhilate Porsches fairly easily. Too bad the SVX is too heavy, it would be a fantastic car that could be made VERY fast. The older 200SX models with the V6 could be another choice. They look like...
...that and they are super sweet. RWD+80's Japanese awesomeness+modern technology=uber ownage
Go here for more S12 good stuff:
http://www.v6-s12.com/SE_Registry.htm
I have to thank you so much for that info. I've been seeing a car just like that for the past few weeks, and I never knew what it was. 👍
Of course, I probably won't be able to find one either like it.
Oh, and the US got Galant VR4's in 1991~1992--and that's it to my knowledge.
Def. a cool sport sedan. It just happens to have the problem many other cars have. Finding a good one.
Anyone mention Mazdaspeed Protegé yet? Definitely one of the better handling fwd cars out there. Would feel right at home on the autocross!
If you're feeling like a 2dr rwd vehicle for cheap, then get an FC RX-7 with a blown engine and drop in an LS1, winning combo if you want to go fast cheap.

(Although I don't think I'd ever stick a V8 in my RX-7 any time soon)
I remember when those came out, and they're fairly uncommon. The Protege probably wouldn't need a lot of work on the suspension either. However, as Toronado said, they're stupidly rare. The closest one on Cars.com is all the way down in San Antonio for $10,000 and 55,000 miles.
The RX-7 though, sounds like a good choice. But the FC, like the Protege, is rare as can be. However, I did find 2 RX-7s on Cars.com last night that sound pretty good. The first is a 1989 w/ 39,000 miles, and a 5-speed priced at $8,800. The next one though is a '93 with a 5-speed, twin turbo, and 9,000 miles for a reasonable $17K. The car is just $2K over what I want to spend, but I'll be checking it out today or tomorrow.
Also forgot to mention that if you can, find a base model (RS) Integra and swap a JDM Type-R motor into it, and you'll have yourself a nice platform to work with. From there, bolt-on mods, possible turbo, etc.

As for being able to find the 240sx, I agree. They're really tough to find, especially where I live. But it's also becoming increasingly tough to find an unmolested Integra, or one without substantial rust to it. I had to compromise for one with a little bit of quarter panel rust, but it's been bulletproof reliable thus far and I couldn't be happier with it.
The Integra sounds like a really good choice. I've been watching a lot of vids from them tracking, and they look as if the stock engine itself, has a lot of potential. But, how costly would a Type-R swap be?
My turn.
A few suggestions as far as cars go:
-E30 3 Series.
Be it a 325is or an M3. The 3XX's are very common, fairly cheap, and have strong motors (both the 318 and 325). Should you choose an E30, I'd strongly reccomend an is model over an i - The suspension is stronger and stiffer, and you probably get those nice honeycomb wheels. A later model (1988 and newer) is slightly more refined, powerful, and IMHO better looking than the earler models. The ultimate choice would be an M3, but they're both rare and expensive. On the upper end of your budget, but still obtainable.
Tough to find unbeat, and without needing maintenance, but I'm still looking.
The thing about these older BMW's though, is that they need to have the least amount of maintenance problems as much as possible. Classic BMW charges $68/hour, and I don't need them to inspect a car, and tell me, it needs a couple parts to be changed out.
-Miata.
I'm the umpteenth person to suggest it, but it's only because they're top-notch cars for competition. Light, communicative & responsive (if you
think left, you'll go left), common, cheap, and they have a huge aftermarket. Anyone who says it's a 'girly car' is obviously insecure, or compensating for something. Supercharger kits are available and make the car very potent.
-Datsun 240Z
I'll admit that I don't know a whole lot about 240Z's, but the one pictured races with the local motorsports club and it absolutely whips the competition. You'll likely have to do a bit of restoration before you start the modifications, but the end result would be worth it.
The Miata is already a possible choice. The Datsun though, just takes time to find.
-DSM.
Despite an (unjust) reputation for being unreliable, a DSM - That is an Eagle Talon, Mitsubishi Eclipse, or a Plymouth Laser - could be a good car to start with. The 4G63T can yeild excellent power gains to the tune of 300-350 HP on the cheap, and the car itself is very reasonable, pricewise. Part of the unreliable reputation is that many DSMers are cheap, and neglect parts until they break... They need to be maintained, like any other car. Early 4G63's produced before 1995 are very strong engines that are immune to the dreaded crankwalk that second generation cars have. AWD cars have decent track potential despite the added weight (Or at least I hope so, I've got one!). They're easy to find, and have a very large and supportive community. Car pictured above is local and has been at a couple AutoX's and is quite competitive.
I'll check the DSM out then. Though most I've seen, are built for drag racing, and seem to be very well suited to it.
-C4 Corvette
LT1 Engine, 6 Speed transmission, fairly common, good suspension and relative light weight make this a good starter car in my books. I'm sure they can be found for under $15k, and the LT1 has a massive aftermarket.
The C4 gen. sounds like a good choice, and it'd maybe take a few weeks to find a good one for around $15K and decent miles.
Edit - One last car.
-Skyline
Strong motor, massive aftermarket, relatively good handling, space to haul a few things around in, AWD. However, it's probably at the upper end of your budget, and hard to find or import.
Also a local car, one of the fastest at the AutoX's.
The only problem with this is location. Most Skylines in the US are no longer stock, and the owners will want stupid amounts of money for them now that the R32 & R34 are no longer legal.
Just throwing this out there, but what about a MX3? I had a V6 as my first car, and that thing seriously had fantastic handling out of the box. Don't know how big the aftermarket is on those though. Maybe get a four cylinder and scavenge some parts of a 323 GT-X turbo? How involved would a BFMR engine swap be? That would make a pretty awesome sleeper.
And Famine has decent things to say about them as well, from what I remember.
Strange choice, and I've never seen a lot of them tracked. I'll look further into them though.