I run the vtx10 in my b4, vtx1 in my 17.5 sc10, vtx10r in my mod sc10, and the copperhead combo in my 4wd sc10. I love them. Smooth powerful adjustable. The pro gauge is great for adjustments. Oh and they have a bad a$$ military discount. With that said I would go with viper. And it is the same as the tekin rs and rs pro. If u are going to run 7.5 and higher just get the vtx10. There is no need for the vtx10r unless u are going to run a real low turn motor. Hope this helps. Tim