| Be smarter -- purchase the M3 engine first. You will be much happier with the M3's power. You can do power-add ons to get around 300 HP NA. I think for a 325is, that is about where you can get with a turbo kit (just guessing off the top of my head).
If you can do EVERYTHING yourself -- you will spend probably around $3-4K. If you cannot, double that price AT LEAST. In addition, you will need to beef up your drivetrain (subframe reinforcements) -- beef up the suspension, brakes, etc.
Don't worry about the engines -- the engine can handle it ... I would say the engine is good for at LEAST 15-17 psi on stock internals, good tuning, and water injection (let me emphasize GOOD TUNING!!!!!!). You do not want to rebuild the engine -- rebuilding JUST THE HEAD -- will cost AT LEAST $1K. If you want say, stg. III VAC work = $3400 (that's not including installation or removal).
I am going with a minor 3 angle valve job this time ... and searching for a radius cut. However, you can get a 5 angle, 6 angle ...etc cut ... titanium valves, the works ... and that is not touching the bottom end at all. I would recommend Corky Bell's "Maximum Boost" -- gives a GREAT background on turbo applications and what goes into them.
Total rebuild of engine = bottom end rebuilt as well -- I would estimate at LEAST $7-8K for a quality job. I know someone will say it can be done cheaper -- I disagree unless you have hook-ups. A quality job, with stiffer springs, pistons, headgasket, pauter rods, seals, etc...etc ... I think at LEAST $7K ... I am guessing more like $10K plus for everything all said and done.  |