So, after the little incident when I was overtaken by a Pug 106, I decided it was time to sort out my S4 and its problems. Took it to Westec performance, Newport, today and Grant and Jock had a good look at it. Turns out that the rattle I have is the heatshield, which was a recall fault, but I am unsure if mine was ever done. The problem with the way the car is running is that one of the cats is toast. So, I am at a point where I need to decide what to do next. Both the cat and the heatshield need to be sorted out. The question is, when the engine is out to fix the heat shield ( mucho expensive ), what should I be doing at the same time, if anything? I had originally planned to sell the car and get myself a 996, but that looks like its gone out the window. I can keep the car stock by replacing the cat with an Audi unit ( 600 quid ) and sorting the heatshield. I can replace the whole exhaust with a full Milltek one ( cost unknown ) and do the heatshield I can upgrade to a set of RS4 turbos while the engine is out and replace the exhaust with the Milltek. I can upgrade the turbos with a pair of Garret ones, plus replace the Exhaust with the Milltek one. Obviously, the highest BHP will be the Garret/Milltek route, but the cost is unknown at this time. Any advice?