Facebook was a waste of time. Lots of admirers on groups but most people in the groups already have one, or like it but aren't in the market. FB Marketplace is a no-mans land of messages that range from "Best Price?" to "Would you swap for a 2015 Seat Cupra plus cash your way" and "It's high mileage/wrong colour/wrong tyres - You wont sell it. Lets do a deal".
Next time I wont even bother on the groups. Autotrader seems the best place as folk are already hunting for that particular car. Pricing is all over the place and I've got M5 owners telling me I'm selling too cheap but the fact is, there are many delusional private sellers out there that think they can sell privately for the same price that a dealer is charging. Dealer offers a warranty, trade-in, finance and buyer protection so why would you buy from a private seller with none of that?
I did toy with selling the M-Performance bits separately and I would have done that if I ended up selling to the trade.
FB is a waste of time unless its free, or absurdly cheap, I see it as the boot fair of selling platforms. When you have a platform that is free and you can randomly, unemotionally message someone, with no risk or consequence, it will lead to fun, games and the gutter of the car selling world.