Was it just plain Thunder before you got the ShenQi? sorry couldn't resist
I've got one too and also suffered a broken wheel but I'm sure it was the roll that broke the wheel, on second thoughts your way sounds better
I have to be honest and say, touch wood, I've had no problems. It's run 5 or 6 tanks now and goes like the proverbial bat out of hell. Sure there have been breakages, a wishbone when I stuffed it into the garage wall, the shell wrecked, but stuck together with supertape, when I drove it under the car. You get the idea All in all I'm pretty happy with it and the more I use it the happier I get. At least now I've got the hang of sliding it into corners, avoiding it spending more time on it's roof than it's wheels!
I guess it's a case of you get what you pay for, anyone spending half the money and expecting all the quality will always be disappointed.
For a bit of fun and no hassle I would be happy to recommend one based on my experience but I'm no serious racer, just enjoy a bit of fun on a Sunday with a few of them up the hill.
Oh and BTW on the site it says "many" not "most" and in my experience slagging off a company's product on the web is not the best way to get your money back
BR
Cal