[suicideneil]

Not a bec issue as such, though running an external one always helps with older style escs. Sounds alot more like thermalling- the heat spreaders & thermal tape tend to let go after a while, then there FETs have no way of transfering their heat to the case which is also the heatsink. Cogging sounds more like either a gearing issue (too high maybe?), or just the software perhaps- not sure if its possible to update it without sending it back to Quark.. good luck that one... :/