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well i bought my car with a mtm stage 1, and have since added a milltek catback exhaust which takes it to stage 2 (right?) so now have bought some Milltek 100 cell cats and down pipes . By adding these will it take it to stage 3 or does it have to be mapped again? As the car is due its annual service I normally use QST but was going to try APS this time as i have heard only excellent veiws of them and Ed replied with a very prompt and courteous email. So if it has to be remapped i will have to get the car down to Qst and will be hopefully having these fitted at the same time, ( so come on grizz ) . Cant believe it takes 5 hours to fit them

I was in the same situation as you (different tuner). I then had the full Miltek system fitted without a remap. I then had it remapped. In my experience you can only really benefit from such a free-flow exhaust system with additional mapping to add some extra fuel at the top end.

Dippy wrote:In my experience you can only really benefit from such a free-flow exhaust system with additional mapping to add some extra fuel at the top end.

Thats the sort of thing I wanted to hear. Mine with remap and cat back is running rich at the top end. I'm soon to fit new 200cpi cats and downpipes so hope it will sort the fueling a bit.

I'll also be doing intercoolers so hope this will also give the turbo's and easier life!

I'll be getting it rolling road'ed to check the fueling again afterwards

You'll know if you have it right. As every K03 S4 owner knows, the engine really struggles above about 5500rpm as the power drops off rapidly, and redlining is rarely sensible. When you have a free-flow exhaust, with the right map the power pretty much stays up all the way to the redline.