The black C6 is my Wife's (just bought off in-laws to replace that stupid Fiat 500.) It's a 2.0TDi SLine (140bhp) with Multitronic, Bose, leather, satnav. It's done 110k and has been in the family since new and has been relatively trouble free apart from the rear wash wipe ******* water all over the electronics in the boot just after it's 5th birthday (I helped the father in law get Audi to pay up for replacing the Bose amp.) Unfortunately, it's just had to have a new intake air throttle. (I replaced the EGR valve while I was on.)
The silver C5 is mine. I've had it 2years now (replaced a mk1 golf GTi as my everyday driver!) It's done 160k and has never missed a beat for me (since 130k.) The guy I bought it off - friend of the in-laws - never had anything go wrong in 6 years either! They don't make them like this anymore! It's a 1.9Tdi Sport (130bhp) with cloth interior. It goes like stink, reliably gives over 50mpg on my 20mile mixed roads drive to work everyday and is supremely comfortable and smooth. Part of me wants to sell it to get something smaller, nippy and more fun to drive, but I just think I'd regret letting this go!
The in-laws have just got a brand new A6 C7 2.7TDi Multitronic S-Line in aviator blue. (See a patern here?) It's very fast and smooth. Better handling than the C6 and bizarrely more economical despite the bigger engine. I think the interior and exterior looks are better on the C6 though. Neither of them feel as solid and dependable as the old C5 though!