which piston S5-GS Sept 14, 2012 9:48:30 GMT -5 Quote Select PostDeselect PostLink to PostBack to Top Post by tbone on Sept 14, 2012 9:48:30 GMT -5 I noticed that there is four options for the S5-GS piston #45030007800a, 45030007800b, 45030007800c, and 45030007800d. What is the differnce and how can I tell which one I need?Thanks for any advice!