Hi F6ETaxi, Autotech did the exhaust, its an X-Force with custom mufflers. I had the original mufflers replaced with ones that have a lot more packing so its quieter, though it still can roar when you push the peddle to the metal. By the way, my F6E is from the original batch of 37 of which there was only 8 in Lightening Strike. It would be interesting to find out how many F6E models have been made in total and how many of each colour. FPV was happy to tell you, but its a bit harder though Ford. I would guess there would be less than 100 in total which would make them on the rare side. If I remember correctly there were about 400 Phase 3 GTHO produced.