i talked to a re builder and he says buy the VALEO with the 8 rib already to install... changing out a 6 rib to a 8 rib is very risky for the belt......it may sometimes look like its lined up but it can rub on the side of the belt maybe very little but after time and wear good by belt and all kinds of bad things can happen .....i took my srt to a shop that works on MB's ...