I read somewhere that if you go to a 48 tooth rear sprocket you have to modify the lower chain guide to avoid premature wear of the chain guide. Haven't seen it on the posts. Anyone hear of this? Mine is a 2003, larger sprocket seems to clear the guide, but the chain sits lower of course. Also my newly acquired bike has an aftermarket Acerbis 5 gal(?) tank. Nice to have the extra capacity, but the mounting systems doesn't inspire confidence (2 little straps up front, nothing holding it at the rear). With the LA-B-Vegas coming up I need to know this thing will stay put! On the posts I see folks using IMS and Clark tanks, not Acerbis , is this why? Anyone have experience with these tanks? THANKS!