[iVTEC]

On the Club RSX forums, various people recommend GM Synchromesh, Amsoil MTF and Royal Purple. Not too many people have noted an improvement with Redline MTL. Of course, the RSX is a different car than the Civic. But both the Si and the RSX have K series engines, six speed MT's and are made by Honda. So there may be similarities. (Oh, how I miss that K-series power!)

I tried the Amsoil in my RSX-S and liked it, although it did not completely take away the notchiness in the RSX 6-speed MT. It was way better than the Honda MTF. I tried the Redline MTL in my old 94 civic and really liked how smooth it made the shifts.

Club RSX members recommended changing MTF every 25K miles, not every 50-60K like Honda recommended. My ASE mechanic friend also recommends this interval, saying that the MTF gets really black and sludge-like after 20-25K.

BTW I have a couple of extra bottles of the Amsoil MTF if anyone wants them. I sold the RSX for a Civic with AT, so I don't need them anymore.