Final comment - BaT (bringatrailer.com) was mentioned and I think that's a very viable option for selling. They've moved a number of M coupes recently and the nicer ones have done quite well. Their auction feels are low ($99 to the seller and a capped low premium for the buyer) and the community there is very helpful in moving the auctions along. Check it out, read their terms, see what they're all about...
https://bringatrailer.com