Audi a6 c5 vs Superb

Hello there. Since i have a license I have been longing for the day, in which i will buy a superb mk1, however comparing the model to a6 c5(facelift all extras) the thing that bothers me is - is the a6 just the better model(given their identical size) for the pretty much the same money(pretty much whats today prices for purchase of both models in good condition and maintaining costs). I wonder whats the difference in terms of insulation, which could be fixed by adding extra insulation to the superb and in terms of ride comfort. I would be very grateful if someone with experience in driving both cars can give me a comparison. 
Thank you