W212 E63 Saloon 2009... should I?

[BFleming]

I've been offered a late 2009 W212 E63 AMG from a friend in the trade. 85000 miles, M156 engine, decent enough spec and a good colour. Wheels have been refurbed, so no longer have the polished faces, but the rest of the body is spotless. The price is lower than the lowest on Autotrader (ok it's £15k) and there is a decent amount of service history. HPI clear too, but I can't get to see it in person at the moment due to... well... you know.
I've fancied something like this for a little while now, don't want an M-car because of their bork-factor, so was thinking S6 (4.0) - then this came my way.
Core running costs don't bother me (tax, insurance & fuel) but I guess there's still a remaining bork-factor niggling away at me.
Am I mad (to be considering it / to not have bought it already)?