never heard of the O-ring problem, and we've sold tons of 6 spds.
Also never heard of that smell problem, i've personally never smelt it either and we've never had anyone coming in complaining
We've never had a new challenger come in with a noisy rear, i've driven all but 2 of the challengers we've gotten in and never heard a noisy rear from any of them
So i guess the answer is no lol, i havn't heard of or experienced any of the problems you listed. i wonder if maybe this was a concentrated group that had some problems??? i dunno