What is the chances of using a 2 1/2 TTA pipe as a template for a 3" jig? Last year I purchased a 2 1/2 TTA pipe on ebay and I have not installed it yet. I plan to see how it fits very soon (keep my fingers crossed). Last year I had a local guy make a total custom from scratch 3" exhaust for one of my TTA's including the DP. Well, it looks very good except for the first 8 inches or so past the turbo. He had to step it twice to make the bends from the frame up to the turbo. Dont get mne wrong it works great but not to smooth with the seam welds. They were not blended in. No need they are small welds. I have a stock turbo on this car and really need a larger exhaust piece to finish the 3" properly. Nothing hits the first time down the road but I developed a small rattle near the frame area. Anyway I might have the answer for the 3"on one of my cars now and another in my garage waiting for a test fit. The thought did pass my mind to copy the 3" but I really wanted another professional brand to use as a giude. As a note from front to back all new with a SS muffler, cross over, test tube, new flex tube, custom DP all in 3" and every seam welded I paid about $1,000.00.