When I put the 3" in my car, I bought a few pieces of mandrel bent 90 degree, 45 degree, and 180 degree angles and some long straight pipes and welded sections together and built the exhaust
system piece by piece by stacking one onto the other. It was less than a third of the price of a shop doing it. I used the 1 3/4" piping from the stock A14 exhaust manifold to the turbo and
the 3" from the turbo to the rear. From the rear axle back, I Y'ed it off into duals. It looked cool with the dual 3" exhaust out the back and sounded like an Indy car. It made everyone turn
their heads and look to se where the strange noise was coming from. I didn't use a muffler at all, the turbo quietened it down enough to keep the police off of me. I have pictures of it
someplace but I do not know which box of pictures they are in. I will post them when I find them. I have hundreds of thousand of photos that I have taken over the years of the whole world so
finding them will take time. I am sorting and scanning my photos all of the time and putting them onto CD's. I have been an avid photographer since I was a kid, sometimes doing 30 rolls of
film a day during a race, musical, or other event.
Back pressure is only needed if the cam warrants it. A good high RPM cam does not need any back pressure at all. Back pressure is for street torque at low RPMs.