about $20 000

 

I'd agree with the comment that getting to 400 hp is not as hard as keeping it going. Your talking 400 RWHP right?

I like the one about being in 5 grand and still being stock! I can relate.

I don't think your going to get 400 hp that will run for long with out a ported engine. I also don't think your putting it to the ground on stock size tires. You would be happier with some suspension/brake upgrades to go with the power.
Pushing stock turbos to 400 hp is marginal at best.
Then there's fun little **** like the AC compressor failing or toe links. Right now I have a broken stud in the exhaust manifold. $500 to R&R the turbos and replace all studs. Just little stuff like that. By the time you get the car in shape to run the HP, I'd guess $10k is a good place to start. Definately will need, boost gage, MP, DP,CB, Intake, ECU, Injectors, FP, IC, hose job. It would be nice to have ported engine, turbo upgrade, y-pipe, rotors/brakes, at least 245's on stock rims, shocks, plugs/wires, A/R meter, turbo timer, radiator upgrade, strut bar, the ability to smell cops a mile away, and a very understanding GF/wife.
Enjoy! I love mine and I'm not even close to 400hp though I'm likely well over $10k