well as above! in here for cs4 fitting on my gsi astra and wondering what results to expect! stage 3 managed 263bhp and 284lb/ft torque. im having vxr injectors and the uprated actuator fitting. not going for the clutch as the one i have has been fine so im going to risk it! high torque map is the one im going for! any ideas would be great! just dropped it on me that i need a sports cat? do i really need one or are they just tring it on!