first of all...
what is the car model and engine u have, what do you look for coz performance is wide subject.....
engine,
suspension,
chassis,
exhaust,
ecu tuning,
dyno,
etc etc
there is no one stop centre....
but atleast for engine,tuning and dyno there is MAG at senawang, exhaust piping at mendobut motorworks (kia 3s senawang), suspension at Absorber Mantap sendayan, and another engine builder+ecu tuner is Awwam Tuning at S2