Initial D: Eheheh everyone is power hungry... a reliable low cost, low boost kit (0.7) would cost about 3k+ in my estimations. For higher boost you'd need to change internals, fuel pump and etc which would probably cost close to 5k... those are my estimations la, with the kit made up until cantik cantik. For risk takers it can be as low as RM1.5-2k.
white bird: I once read that modifications, if inspected by puspakom and approved can be legal... but Im not sure if its true or if I remembered wrongly or not, so here am I asking lor. Your car will have to go through several tests to determine road-worthiness.