Weird, I haven't had the need to shim anything. Did you get the Mantis TXS or the original Mantis?
I have the TXS and I really haven't noticed any durability issues. Like I said about the rear hubs though I think that they flex a bit too much however, if you look at Duratrax stuff, their parts are so rubber-like they might as well have Michelin stamped on them. It does make some sense though, to have a part that will give vs. snap: especially for new(er) drivers whose offroading adventures consist of the backyard and who
might do some club racing at best. Though I wouldn't have any fear racing this truggy, it certainly wouldn't be without a few upgrades.......maybe some day. According to my friend at the LHS, I'm the only one he knows around here with an E-truggy: so I'd be racing against myself.
I ended up putting some o-rings in the diff drive cups to help with the dog bone issue. I don't remember if they were originally there or not when I first got the Mantis but it seems to be working thus far.
I decided to spend my extra $$ on a Losi Strike instead of upgrading my Mantis any further at this point. Maybe when I have some extra coin I'll buy the upgrades I was thinking about (or if anything breaks), but until then it can stay stock.
Every time I take the Mantis out, my son is trying to touch it. I set the remote down the other day and had picked up the rear of the trug to check out the missing dogbone: let's just say my son figured out how to mash the throttle on the remote. Seconds later, the madness stopped and I was able to recover from all the rocks and dirt which were slung into my face by the front wheels. So I'm hoping that having a car around that he can learn with which doesn't go 50mph (yet!) will be a good thing.
Actually, I'll be picking the Strike up today so my son will be slinging more rocks in no time: though, not at my face!