umm.. I wouldnt consider a 400whp evo fast. more like quick

 

I disagree, most people can't even control a stock Evo. Sure it is easy to drive in a straight line during pulls and stuff but not easy to truly race the car on course.

I've been driving my Evo for 6.5 years and 400whp/400tq feels stupid fast to me.

 

personally it can be done on pump gas, im sitting at 410 on 91 octane here in socal, and ambient temps been in the 100s. 400 -450 is possible, but you will need an improvement in flow mods. Aggressive cams are a must, s2s kelfords etc. Now I did mine on an fp red. So as someone else pointed out youll need a turbo that flows similar rating. So to get 450 hp youll need a stock appearing upgrade, red equivalent or bigger, and more then likely youll need a bigger/ported intake mani and tb. The ported exhaust mani will help and also be discreet under the hood if the 5-0 is a problem in your area. To be honest ive ridden in a 35r evo making 500 on pump here, beast, but laggy in a sense. Personally id rather have a 400 whp car making that power range for 4k rpms then 2-3k 500 hp car, because to me it feels faster.
So in the end I forgot to look at your modlist, assuming your clutch and other parts dont wear prematurely, will probably cost you around 4-5k in parts and labor with a tune, give or take for a shop to do that for you depending on your modlist.

 

What is your definition of "reasonable"...?

 

It's possible to get very close to 400hp on a mildly modded Evo on pump gas but you need to run lots of boost, ie have very good pump gas. You can see my sig, Tom at TScomp wound the boost up to around 29 psi and on a Evo 9 with good Aussie 93 oct fuel I'm knock free, but I'm really at the limit with my mods, I know my injectors are running around 95% duty cycle, close to max. I'm going to throw a o2 dump/housing and a exhaust mani, probably a Toxicfab, in and get some porting done and add some bigger injectors and see if Tom can push over 400hp, maybe 415 to 420hp on pump gas (virtual dyno), but as it's been said on the thread I started for my tune my car is a bit of a freak!

 

The money I have currently = the horsepower tht is attainable at this case 330-350