peejay, are there any major differences between S3/S4 and S5 discs? I see the S5 disc is cheaper on the Mazdatrix website.

I felt like I'd be losing tenths of a second on an autocross run from the 1-2 shift using the stock clutch....while I know that's not a lot, I did lose a place by a couple of tenths at the last autox event.

I can imagine that it would add up to more around a track.