The ZZR is a 2000-2002 ZX6R. I have looked over the ZZR and it is 95% identical to my 01 I had. The ZZR isn't going to be any better for long rides than the 636. The big difference between the two is the 636 will have less weight and about 15 more hp. I would be up for either one, I loved my 01 it was a fun bike.