The only issue I have with the b4 is the bumper and front arms. My bumper is paper thin after a few weeks. granted they are super cheap, lol. I like the rpm front bumper, but it sticks out too far and cause lawn darting. I might use my heat gun to bent it back a little. The front arm really, really, really dont like pipes. If you dont hit pipes its fine, lol. And on hard packed tracks, the rear tower will break on roll overs. Again, dont crash. the b4 in the hands of a decent driver is a beast on the track. the replacement part are pretty cheap. My main concern is the b4.2. Something has changed. I think TT is making them for AE now, and to be honest they sucks at it. I never saw all these QC issues in the 4.1wc. I heard cliff lett mention in a pod cast that TT is making some of their kits and I think they are probably making the new kits. I would imagine that as new or upgraded kits come out, that TT will be doing much of the manufacturing. When AE owned its self, these issues were much more rare. I fear for the future of AE with TT in the picture.