[8695Beaters]

The easy gains on an S2K are the ECU (Hondata reflash), spark plugs, a good intake, header, and exhaust. The valve springs and retainers are only needed for relaibility (and since you autocross, you will want that). You can do a cam, but there's about 3 horsepower to ber gained and it's only from about 7500 RPM. Plus you lose some of what little torque the S2K has. There's no gain from cam gears, since i-VTEC does its own tuning anyway. Also, don't swap the valves. You will not find anything better in the aftermarket. There might be some power left in underdrive pulleys. There might also be some power left in the intake manifold too, but I'm not sure. You could also get some higher compression pistons, but that's pushing it on a street car. After that there is forced induction, but you may not want to go there.