I bought an M6 from a member here a couple years ago and the seller accidentally sent me an M12 - it was in the wrong box . I just made up the difference and kept the M12 as swapping from the US to Canadia was going to be expensive plus I figured it could be useful. I've been hanging on to it as a backup; and halfway had thoughts of installing a sub that could actually use all its power, but still haven't done anything with it other than look at it.
I hadn't been thinking about selling, but might be tempted by interesting trades. Shoot me a text - let's discuss.