Need some help if any one will oblige? I want to change the full exhaust system on my S4 V8 to Milltek and have got quotes and was about to put my order in until one tuning specialist chirped up and said 'I doubt whether replacing the CATS will make much difference as Audi already put sports spec CATS on the S4' Can anyone let me know if there is any difference and if so by how much bhp? Seems a waste to pay £1200-1400 for something that won't give a significant amount more. I am however not 100% convinced by their comments. /ubbthreads/images/graemlins/confused.gif HELP!!