That gives you a cross section of about 1.7", which is where I was when I said it needed more.

A 2" bypass, like the stock PSE, has a cross section of 3.14" (double what you have) so you really should have done two 1 3/8" per side. :(

Yeah the holes must not be big enough. Did they at least drill the holes all the way through the pipes? As you can see what I did in the internal bypass thread, two holes each side around 1 inch. Then I used a chisel to connect each hole. I can definitely hear the difference in the car with the windows up. With them open and the top down, big difference. Under a bridge or in a tunnel it is pure GT3 mode. My wife says she can hear me coming down the street at 30mph. If I get on it people always look. So I would say the mod works if done right.

Well. Darn. Yes, it sounds like the problem is not enough, or large enough, holes. I asked him to drill 1.5" through both sides of the pipe, on each side. When he had cut the 'window' to get in there, he thought that the pipe wasn't big enough to handle 1.5", so he went with 1 3/8".

http://986forum.com/forums/uploads02...1561739079.jpg

If he opens it back up drill 2 holes on each side, all the way though the pipe. I used a step bit, so I could only make the top of the hole full size. Both of the holes on the top of the pipe are 3/4 of an inch. The bottom holes are smaller. I put it back on the car with these size holes. I felt it needed to be louder. So I took the muffler back off and used a chisel to connect the holes. Basically I went through the pipes on the side of the muffler, placed a chisel in the hole closer to the end and hit it with a hammer until the holes connected.