The reason I decided not to go with the Wiseco is the CR. If I plan on making my goal of 600-650 I need close to an 8:1 8.5:1 Ratio which the Ross pistons will give me with the 2 mm MHG. A friend of mine used Ross and they didn't slap, he had spent a lot of time putting his engine together with everything as close as he could get it and she ran great.