all we run are Ultramax's, we have 2 badmax's one Element and one Excentrik. I like the Excentrik on bigger tracks, the badmax's work great for indoors or tight little tracks, same with the Element, the only thing we have done overall is take some cross out of them compared to the setup sheet that Umax has, rest of the numbers are inline. great to work on and respond well to changes, I will say, the Excentik will change alot even with minor changes
-Matt