Bob, it's the latest edition the M145...a 2013MY.. badged as a Sport... aside from a few extra horses, - I believe that brakes, skyhook have all been tweaked, as well as the front end revisions and the interior... But most importantly it has the MC software in the Auto box... See what Dicky Grace had to say about it..in a thread somewhere on here..
It's another step forward from the GTS... perhaps not quite the leap from the 4.2.. but you'd certainly notice the difference.. For what he's asking - that is now the cheapest around I believe.... those with main dealers £75k +...
and had it been around a few weeks ago before I did my deal I'd have been making a very punchy bid for it..