Dear God no.
@slidesquad#1; I was waiting for you to post! Always liked your VI

what can you tell me about owning the Evo? What should my dad be looking out for and any recommended mods?
It'll depend a lot on the particular car you've got. If it's been looked after, they are quite reliable cars. Apart from maintenence, everything I've done to mine has been because I wanted to, never because I had to. Keep on top of servicing, and treat it with a bit of respect, and you shouldn't have any issues (though I doubt your dad is going to be popping helis anytime soon!).
Umm common issues...the lifters (lash adjusters) can get clogged up and make an annoying tapping noise when cold, that's pretty common. You can take them out and clean them, but new sets aren't too expensive, and should be good for a VERY long time.
The suspension top mounts (and sometimes the shocks) can wear out and knock quite a bit with age, but shouldn't be a problem as you have coilovers anyways.
The IVs had crankwalk issues, but again Vs and newer got a different block that isn't as prone to it.
Parts aren't cheap from Mitsi. If you break something you're gonna have to pay, and it's often cheaper to get an upgraded aftermarket part than replacing the OE item.
In terms of modifications, your old man already has the basics done (though double check the condition of the filter, the older HKS ones have a tendency to not filter very much out once they get a bit old from what I've been told). You can probably up the boost a little bit, but I wouldn't run more than 16/17 ish psi on the stock fuel pump. With a Walbro pump the standard fuelling and internals
should be good for 20 psi, but at that point you need a remap or aftermarket ECU, the factory one won't let you boost that high. I'm hitting boost cut in the higher gears at 17 psi, and it's pretty nasty. Making sure that your fuelling is right is essential too!
You should be somewhere close to 220 kw (~300 hp) at the wheels with that, and it'll be a lot of fun in addition to having decent reliability. I'm getting my fuel pump in sometime this month, and still debating whether to chuck in a powerfc I bought about a year ago, or selling it off and remapping the standard ecu.
More power than that would need bigger injectors at the very least, and then more aggressive cams, bigger turbo...pretty much depends on what you want out of it, and how big the wallet is.
Your Teins should be more than enough for a street car, and the factory Brembos are awesome as well, especially with some decent pads. Keep in mind that they can get quite noisy around town though. I have a set of cheap and nasty road pads that are quiet for the street, and a set of Endless carbon ceramics for when I know I'm gonna be giving them a hammering. The nice thing about the calipers is that it takes longer to jack the car up and take the wheels off than to change the pads.
You're lucky in that the UK probably has the biggest scene for the pre VIIs outside Japan. Check out lancerregister.com, there's a heap of information out there that'll come in handy.
Any specific questions, ask me, and I'll try to find out for ya!