Am currently having a Chip Torque Cam & Chip package installed on my ED Six. Have been using Garry Scott of Newcastle to carry out Mod's and prior to the installation he advised me to have my exhaust modified. I was already running Pacemaker headers and a 2.5" straight through system from the Cat back. Dyno run showed 152 BHP and Torque of 880Lbs. The Mod's we carried out included extending secondary pipes from the headers to 18inches then connecting to a new 2.5" high flow cat. The result, 163 BHP and a Torque increase to 930 Lbs. Has anyone else carried out this type of mod. Only other mod I have is a K & N Filter.