ok, so basically, everyone above me except for the first guy are stupid. you have a manual B18A1 not a B18A (big difference) and plus, having a manual helps a TON. if you want a cold air intake, its about $200 and adds about 10-15 hp and you can easily install it yourself. and as for the douche talking about water getting in there and locking up your engine, its true but you just need to install an air bypass valve halfway to the manifold and if you get the filter wet, the water won't get in your engine. you can also do the exhaust. You can enlarge the pipe diameter, or you could replace the catalytic converter with a high flow catalytic converter or even a test pipe. an exhaust mod could add 10-20hp. you could also buy a hondata ecu chip for your car, but that's about $500 for the s300. Simple maintenance things like spark plugs and fuel injectors will help and will keep you running longer with better gas mileage. also, dont forget to replace the timing belt, if it brakes, you could ruin your engine. and check your head gasket while you're at it. if you want to get serious buy parts individually for a turbo system. it will take a while but it could get you from 135hp to 300hp easily. lots of parts to buy and takes a while to install, but if you want power, you have to pay for it. sucks, but everyone's looking for a cheap 20+ hp boost.