View Full Version : s4 back box. couple questions

08-13-2007, 10:12 AM
so has anyone used the s4 back box as an oem exhaust upgrade , if so did you notice a difference in power , spool time , ect ? Thanks shound like a good cheap upgrade imo.

Thinking of doing this ? Im running a 2.5 turboback to my stock a4 back box with no resanoator? would this be louder?
Any positives or negitives ?

thanks guys. [az]

08-13-2007, 11:41 AM
a "muffler" ?