A6 s-line vs. S4
#3
#5
Re: A6 s-line vs. S4
Try this link - S4 is the performance variant of the A4; A6 S-Line would be primarily a trim enhanced variant of the A6.
#7
Re: A6 s-line vs. S4
A6 is a much bigger car. I had an 02 S4 and the rear seats were very tight. The A6 leg room is great. I have the 4.2L engine in my A6 so it's quick. It's also quieter and very smooth so the speed is deceiving. I loved both cars but prefer the A6 now.