The 11.8:1 compression will provide you with more acceleration than kits with 11.3:1 compression. However, this kit cannot be used with original cams, it requires a more aggressive cam (maximum valve lift (tdc) of 2.1 mm) and has very deep pockets for use with rsr valves. The 109-mm size means that the housings must be modified on non rennsport models. If you have a European rennsport model, these would be slip fit. This kit also requires the larger o-ring seals, part # 96410440180 and larger base gaskets, part # FVD116929. Mahle pistons are forged for substantially higher and more uniform strength over pistons that are cast. Mahle cylinders are manufactured from st52 steel which has extremely high thermal resi...(choose a part on the right to read more)