From what I can gather, ours are strong. There are some high-torque/hp guys on this board that are still running the stock axles. I think only a few have upgraded to the Raxels. If you aren't pushing some serious HP, then I wouldn't waste my money on upgrading them, unless they are shot. Spend you're $ elsewhere. Just my .02
These are highly engineered precision vehicles, the first step in diagnosing the problem is to strike the suspected offending part sharply and repeatedly with a blunt object, then re-test.