I never ran in the mud. Wouldn't put the car through that, especially as I'm only a club racer.
They were the mugen bearings which I've never had a problem before. I replaced them, blowing the grease out with a compressor prior to installing the inside bearing and the car felt perfect last weekend. I think that the 14t was a bit much, so I've switched back to the 13t. Set my new PB qualifying run last weekend which was nice too.
The car was on rails.