If i was you the first mods i would do would be injen, toda headers, and 2.5 inch exhaust followed by a k-pro. Other things you could do would be PRC (JDM) Intake manifold. RBC is no good unless you have cams.

I have a 150kw atw dc5r and i am still running std clutch and flywheel. Rolling start the car beat a mates 34 GTR with only 135-140kw, altho the car was slightly stripped.

I/H/E and k-pro should see 135ish kw. decrease the weight and get light rims and u'll have urself a quick car