of engine
u can change air filter (K&N o open pod like apexi's)
denso idrium spark plugs
lightened & Dampered Crank Pulley
Port n polish
Performance Cam shaft
Adjustable Cam Gear
form work exhaust system (4-2-1 til the end :P)
it all started one night at traffic light. that time just drag the car up to 0.5 bar and the check engine light lit on. thought it would just be minor thing and would reset by itself on my next engine startup, i...