Got some pictures and a drawing to show everyone. First picture, new side pipes sans clamps. I needed to end up with 2" extra in length (the old pipes were too short). Result? Perfect!
Oh, the insides of the Classic Roadster side pipe (and as DV notes, virtually every side pipe used by every one else):
A little drawing I made up for my web site. DV is right in his description of how the old side pipes work (paraphrasing): bang into a wall, slip though a small hole, then through a bunch of smaller holes, then bang into another wall and out:
And finally, when I really want to make some noise:
I'm going to a muffler shop tomorrow to see if they can weld an O2 bung on the right side collector. I should be able to hear what the pipes sound like by this weekend!