The blower for the ITR and GSR are the same (M62?), but I have heard that the GSR pulley is slightly smaller. This would give a little more boost. Check out the "forced induction integra" forum at hostboard.com. That's where all the jrsc heads hang out. Or just email James Watts at JR (wattsj@mossmotors.com). He has always answered my questions. The jrsc website (jacksonracing.com) has a dyno chart that shows a 98 ITR making about 209 HP at the wheels (255 gross HP) with just the base model supercharger (plus Boost Timing Controller, MAP Controller, and high pressure fuel pump). From what I have read this is a little high (just like all other claims from performance part makers). However if you use some other form of fuel management that can be tuned you should easily get that much HP. The JR MAP Controller makes the Air/Fuel ratio much too rich at high RPM. This means that your car will run safely (i.e. no detonation) but it reduces the peak HP.

I've had the jrsc on my R for almost two years. I love it. It doesn't produce the high peak HP of a turbo, but it fits the type of driving I do most (winding country roads). It provides great low end torque which is what you need if you are constantly turning, downshifting, and dropping into lower RPMs.