I ran across a cheap nearly new Dynomax 2 ½" cat back system from a wrecked GT Mustang, plus a couple extra odds and ends of same size pipe I used to add in between the H pipe and the mufflers. These were curved a little, but I could have used straight sections. I used these as I had them instead of buying more pipe.

I didn't get the ends REAL even, but close.
I had pieces from another 2-1/2" system that I cut up - that's why there are slight bends in the pieces I added. I could have added straight pipe sections just as easily, but this is what I had so I used it. It did help a little to keep it tucked up.
I used stainless wrap or band type clamps of the type often used on heavy trucks. You can get it at an auto parts store for about half the Summit or Jegs price. Just butt the ends and bolt on clamp - it comes apart real easy!

- macx