I have my rear wheel off right now for the first time since i've owned the bike. i was inspecting the sprocket teeth and noticed on quite a few built up ridges of metal on the teeth edges. how normal and to what extreme until this should be dealt with ? also if and when a replacement sprocket is needed what changes if any have people made and for what reasons/ type of riding ? on a different topic what are some peoples fav aftermarket front brake and clutch calipers ? the stock ones suck IMO so big and bulky feeling.