I tried the 13x6 and 14x4 zingers today and I think I liked the 14x4 better. The 13x6 seemed to have less thrust and definitely more speed but I really don't need the speed with an Edge 540. I'm going to try a 14x5 and 6 to see what I like the best. I will probably try out the ASP carb upgrade soon just to see what the extra power is like.