as most who have seen me run will attest, I tend to hit a board or two. However, the only parts I have ever broken on my Rev3 or now Rev4 are the old style front end arms (once every 10 race days or so at most). Needless to say, these are easy/cheap to purchase. Now that I know how to reinforce my bodies (and I love the sturdiness of the CEFX and/or the Speed12), the most pain I get these days is from chunked tires...