I'm about to get a low mileage Version 5 STi reconditioned engine fitted and whilst it's out of the car I wondered what sensible (relatively cheap mods - say total expense of less than £500) mods I should consider (for increased performance/response obviously!).

 

Ported cast headers from API and a Ninja sport cat D/Pipe and a green cotton filter.
Alternative is to make the car faster still by doing the chassis first, Whiteline roll bar(s) and several other cheap but effective parts and a very good alignment job.

Just my opinion!

Graham

 

Since you have the engine out and it's sooo much easier to do now I'd say new cams. I'm not exactly sure how much they run but the right cam can make a huge difference and it's one thing that you really need to pull the motor to do if you decided to down the road.

I know cosworth makes cams and other engine peices for subaru now and they know their **** when it comes to building motors.

 

Unfortunately its not just the case to fitting new cams the heads would need to be worked and the price would soon go over his budget. If 500 is your budget then I would suggest keeping an eye on the sale section and look out for a complete decat exhaust system. And a New green panel filter or equivalent. And see if you have money left towards ported or aftermarket headers.