[RickFLM4]

I had a 2010 A6 and a 2013 S4. I think the 2012-current A6 is nice but much more luxury oriented than sports oriented. Somewhat Lexus-like. The 3.0 SC engine is great and so is the interior, particularly small details likes knobs and buttons. Audi MMI with Google Earth is better than iDrive IMO. Overall, very nice car and gets you the extra room you seek but don't expect it to be a performance-oriented sports sedan.

I drove Lexus for 14 years before Audi (including a GS for 10 years). Their styling is polarizing and I am one that hates it so not a car I would ever consider. I also wouldn't personally consider a CTS-V. So between the three I'd go with the A6.

Have you looked at used Jag XF / XF-R?