will a catback exhaust add any horsepower or is it for strickly sound. also will performance valve springs add horsepower. and besides nitrous what is the easyest way to add alot of horsepower inside the engine.
umm catback exhaust CAN increase horse power not u wont' notice the difference especially in a civic. most people have it for sound and looks. valves... not my area so not sure (sry) and easiest and cheapest way to gain HP is Forced Induction. there are other options but it will cost u alot of money. just search thru other cc member's cars and see how they do it and what u like. thats the best way to go.
