I'm not keen on high-revving engines, but as the revs pass 2K it's already making 360 lb.ft/500 nm, so it won't be necessary to rev the nuts off it to make good progress.
I've spoken to the indie where the maintenance has been done for the previous (eight years) owner, and was told he was a long-term customer with several Mercedes, and very particular; if it needed doing, it was done. Rear air bags, dampers, suspension arms, engine and gearbox mountings were mentioned as well as routine servicing. I reckon it's a good 'un.
And finally, I can swap in the later NTG2.5 COMAND, so I can play my music without faffing about. I've run out of reasons not to buy it, so (unless it's gone; fingers crossed...) I have to, really.