I had a '12 S4 6mt as well .. sold it after 18 months - just picked up a 991 C4S .. whoa no comparison - there was nothing wrong with the S4 (even with a revo tune, just bland) .. my winter DD will be a pepper diesel

 

Granted I went from a '12 PTT to a 13 S4 so it was a little more severe step. The car itself is not bad but I found the seats to be brutally uncomfortable!
I kept it for 5kmiles and traded it for a 13 Cayenne GTS. Now I have the best seats in the world coupled with storage the PTT was missing.

 

Now that you mentioned it - the seats in my 12 S4 were the most uncomfortable as well!