12 psi max out of the stock ecu/turbo. Get 550 cc injectors and an AFM from a lexus v8 and you can run almost 1 bar - which would be good for a mid to low 13 second quarter mile. Good luck losing weight because the whole thing is made out of steel and not light. A 3" exhaust will be the best mod, and you can get a k&n filter and chop off the front of the stock box. The biggest hassel is keeping these things reliable with a ton of miles on them. Copper plugs are fine, and I wouldn't suggest any synthetic oil that is too slick, because the rings can get loose, and they spin bearing VERY easily. Supraforums.com has a great MkIII board. You'll also most likely need some form of an aftermarket BOV because the stock ones don't last either. There is a VW/Porsche/Saab plastic model that is cheap, but you'll have to research a part number. Anything else I can help you with, I use to have one but I am glad that is no longer.