you can't gear properly for a 2650 w/ 6s lipo in an 8ight unless you don't plan on racing.. LOL
you can't gear a 2200 w/ 6s properly for that matter.... if you want 6s go w/ a 1300-1600kv motor other wise stick w/ a nice 4s setup. To be honest w/ that 2650 you may almost want 3s lipo out on the race track.