I/H/E
Thats...Intake, Header, Exaust
Any of these will be a good start to more HP.
Intake will give you some top end and totally change the sound of your car.
The Header(If you can find one) Will release alot of power in our cars as it should remove the first cat.
And the Exuast we don't really need, but it may give a little more HP, but not much if any.
The intake will be the easiest to install and will probably give the best bang for the buck.
Any piggyback (or standalone) ECU options for the stock Protege5?