The RSX-S makes 200 hp, the DC5-R makes 220 hp. My guess is there's a different intake manifold and header, plus slightly higher CR and different cams. But, since nobody in this country that I know of has opened up a DC5-R motor, I can't be sure of this with any certainty.

The '96-'97 JDM ITR motor is identical to the US-spec version. The '98-'00 JDM version has a different header and slightly nicer version of the same intake manifold along with slightly different calibration of the ECU. The '01 JDM ITR has CTR cams.