i currently have the stage 1 sos in my 2002 ap1 s2000. i feel like it could make more power. i feel like theres really no cold air entering the system. so i was thinking about buying there heat exchanger. what do i need to put this in this system. will i need to buy another water pump. also i was wondering if a 3.2 pully help give me more power. just give me some things i could do to improve this system

 

If you have a stage 1 kit, the upgraded heat exchanger will only do so much. If you're not putting it to track duty then I don't see it making a difference.

If you go with a smaller pulley however, you're going to need a lot of things, EMS, injectors, fuel pump, the pulley itself, the upgraded heat exchanger would be ideal in this case. Potentially a better water pump as well.

With a 3.2 inch you can expect closing in on 400whp even with the 1220sl despite what the SOS pulley chart says. Numbers are all over the board and well expect 380-410 in my opinion