Well, I keep a small 1/18 offroad track in my backyard, have seen many small scale RC cars taking all kind of abuse there and I have to tell you that the AE RC18s are by far the toughest. They just keep going. Out of all my own RCs the RC18s require the least wrenching, and they get BY FAR the most wheel time (a track in the backyard can do this
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Just get the MIP super diffs and their CVDs and yo should be set. If you drive mad overkill brushless setups the diffs like to go from time to time, but that's nothing like the Losis. On my own RC18 the diffs last a couple months, with almost everyday driving in summer.
Just now, after 2 years, we see some servos going bad. But most have heavily modified (or even glued) servo safers.
Another thing I'd suggest is the Driven Productions gearcover, and their draglink. The gearcover is a must for offroad. And the drag link is a must anyway.
Those 4 mentioned upgrades will make them bulletproof.
Forget about the Vendetta/Shark... those people are always wrenching here. And the Kyosho is just a stupid design... plus parts may be hard to get and are often expensive. The HB Minizilla is a joke, IMO. MQ could be nice too, just never seen them much racing here. Same goes for the Trinity, never ever saw one, can't comment on them.
I vote for AE on that one. And of course the XRay is nice too... just a bit too nice for our harsh offroading. If you drive indoors, get the XRay.
Daf