Agreed, but you'd be buying a 55K, and my Turbo Nutter Bastard days are (mostly; there's still the SLK...) behind me now. I'm comparing the VW to the pre-facelift (my favourite) CLS500. In any event, the M113 was dropped from the CLS range from the 2006 model year.
That car is up for £9K; nine years old, 40K miles, fsh. Supposing you could find a petrol CLS the same, I suspect it would be up for a lot more than that.
Sadly, my personal circumstances preclude my buying a sleek four-door saloon or coupe; I'd have to put (often muddy) dogs in the back seat. If it were otherwise, I'd seriously consider that particular Passat CC; it just looks so good, classy and dignified. Like a 'proper' Mercedes, in fact...