Great first post mate!

There is plenty of information on the forum already and most things can be found out with a search. Just try different key words etc. Also its really good to follow build threads for good ideas. See what is good power that wont be over the top.

Personally think that 200-210kw at the wheels is perfect! I have that and its great. Not over the top for the engine to.

For your car i would surgest going twin scroll turbo. Get a vf37-36 and you will love it! Should cost about 2k and then another 1.5k for tuning and new sti TMIC.