My 2003 749S was 14 front/39 rear. I went up 2 on the rear, as 14 is the minimum they recommend on the front before the chain starts to suffer. I beleive that was one of the differences between 749 and 749s, 749 has 15 on front (no idea about the rear).
Anyway, going up 2 on rear is like 1/2 a tooth on front, and it does make it a lot more lively. 14/41 now and the only problem is running out of top end a bit on the track. Nice an snappy out on the twisties though
