Well, you could get an aftermarket muffler or cat back system, that will give u about 10-20+ hp. n dont forget the intake as well, for better colling n more 7-10hp.an great way to increase hp for ur rsx and cheap is the famous n20, yeah it can can boost 50/75 or /100hp depending of what ur car can handlle, if you add everything that i told you, it would make ur rsx sleeper bad ass mofo!!well good luck!