Yes, both those pipes might be a little to harsh on the bottom. The new Gen 5, 5 ports are a little smoother than the previous. At our last race I had the gen 4 and my son had the gen 5. (both 5 ports) It rained and the track was real sticky, the kind that made your car 3 lbs heavier at the end of a run. There was a noticeable difference in the 2 motors on the bottom. the Gen 4 had more bottom because of the lighter crank, but most times you would want the smoother one.

Rex