I have the SiR II in my 96 civic... it's rated at 170 horses. My friend has a 99 si with the a2 rated at 160 horses. We both have the same mods I/H/E & good suspension setup. We race every now and then just to see where we are at in tuning and how everything is holding up... I usually pull on him by a bumper. I know my car is faster because I am running the virgin p28 and still pulling on him. My real question is what is different about these motors to make mine have 10 more horses... I know the compression is different but only by .2 and that should not create a 10 hp difference. Does the SiR II have more agressive cams or what??