I'm not one for American cars but I was watching spike one day and they had a turbo kit for the camaro SS and it boosted it an extra 100 HP. I was extremely impressed with the kit too, intercooler and hose clamps and even a catch can and everything included with the kit for a very low price for the quality kit they sold. Here's the thing though with your choices; you can buy the $35,000 (around that much) SS and a $2-4000 turbo kit and have as much HP as the the GT500 mustang which is around $50-55000. I would go for the camaro. personally I think it looks better too. You should broaden your vehicle search for the money you have. How about a used GTR?
That's why the 5.0 is still on the list (which is superior to the Camaro SS in virtually every way IMO).
For $5500 you can get a procharger kit for the 5.0 which puts rwhp in the 520ish range, which is higher than the GT500. I doubt that turbo kit is anywhere near 2 grand, btw, the ones I've seen are 6-7k, and a pain to install.
Equipped how I'd want it, a 2012 Mustang would probably run about 34k. Add 1200 for brembos and 5500 for the supercharger and I'm at 41 grand. That's only 4 grand less than the new Shelby I'm looking at, and my brand new 5.0 now has basically zero powertrain warranty.
I haven't seen any used GTRs for less than low 60s, which is out of the price range. There's one on autotrader for 58,5 but it's got over 40k miles on it and needs brake work. Something to think about though, I'd probably have to wait a year or so to really get a good one down into my price range.
He's looking at a 500+hp car, has already called a 330hp or so car "too slow", and you suggest a 250hp hatch?
Heh.
Honestly I don't know if the GT500 is the way to go right now... We know that the 5.4 is now quite long in the tooth (but well proven) and probably due for a replacement... 5.0 cars will be somewhat better balanced in corners given proper suspension work (see Boss) and can match the GT500 in a straight line easily enough... Iunno.
You've hit on what might be my primary concern. The 5.4 is a great motor, but it's definitely been around a while and could probably be significantly more efficient with some updating ala the 5.0. There's also rumors of it getting punched out to 5.8 liters and making 620ish hp for the 2013 Shelby. But if that happens Shelby prices may be back where they were a year ago, 5-10k over MSRP, and I won't be interested. Never know though.
Mild supercharged 5.0s are generally making 510-520 rwhp from what I've seen, while the stock Shelby is 475-485. But, how reliable are those 5.0s going to be? I'm not sure anyone really knows for sure. You're talking about 11:1 compression motor with cast pistons in the 5.0 versus 8.4:1 CR and forged pistons in the Shelby. Not too tough to see who's going to win the longevity title with that.
The valvetrain in the 5.0 is where the magic is happening though.
Actually I found a comparison where they compared the 5.0 to the 5.4 at varying boost levels:
8# KB GT 545hp 461lbft >8# eaton 478hp 459lbft(stock tune)
12# GT 650hp 532lbft > 12# KB Shelby 616hp 539lbft
15# GT 710hp ???lbft > 15# KB Shelby 637hp 576lbft
18# GT blew oil pump 2x cause of aftermarket harmonic balancer < KB Shelby 672hp 606lbft
At 8 pounds of boost (bone stock on the Shelby) the numbers look pretty bad for the 5.4, but the 12# numbers look pretty good for the Shelby IMO. An extra 4 pounds of boost is nothing to the Shelby, but 12 pounds on the 11:1 CR cast piston 5.0? Plus I don't think you're really going over 8 or 9 pounds on the 5.0 with 91 octane, so the 5.0 is going to be limited to the 550ish while 91 octane is easily good for 12 pounds (most say 15 pounds) on the Shelby, = 616 HP.
Plus there's the tranny issue, the TR6060 in the GT500 holds up really well. I dunno, lot's to think about. Like I said, the point you made is was one of the major cons IMO.
As Eric says, it sounds way off, You'de be b etter off with a Shelby.