Originally Posted by badfish
BMW-M-Mexico reports nearly zero difference at the track with 20s. I run 20s currently. The only reason I want a set of 19s for track is for the better tire choices. There aren't a lot of good tires in the 20" size. 18s have the most options but 18s won't fit my BBK.
No offense to either of you but really, 20s are not for trackwork (unless you have a GTR, and even they're looking for small track wheels). One anecdotal trackday with no data and an unknown driver is not exactly proof.
CCW one-piece wheels will fit the Brembo 15" 6 piston monoblock BBK, hard to believe but true.