When I first started work on my V6, someone here gave me a procedure for creating a cut through without using these. I would credit the originator, but no longer remember who it was. Basically, you first drill a hole straight through the cross member at the appropriate spot using a 12" long drill bit. It takes some work to get the holes in the right spot, and as I recall, I drilled smaller holes on each side, then used the larger bit to be sure the guide hole (you will see why I called it that in a second) was at the correct angle. I have forgotten the bit size of the 12" bit, but it is the same size as used on a standard bi-metal hole saw (I think it is 3/8"). You put this bit in the hole saw in place of the original bit, and then use the hole saw to cut a hole straight through the cross member. The size of the hole is up to you, but you size it based on the large diameter exhaust pipe that will eventually go through the hole. I think I used a 3 1/4" hole saw and whatever exhaust size matched that OD. I just bought a foot of it from a muffler shop for a couple of bucks. If I had it to do over again, I would have gone with a slightly larger pipe.
Cutting the hole at an angle (the saw is basically running parallel to the car's length, but that puts it at a sharp angle relative to the cross member) is easier said than done, but it is doable because the 3/8" holes keeps the hole saw properly lined up. One saw lasted both cuts, but I broke multiple drill bits in the process. Those 12" bits get expensive and about half way through I realized that there was really no need for an actual bit once the guide hole was drilled and switched over to just 3/8" bar stock. While the hole saw is round, the resulting hole is oblong due to the way it cuts on the angle. (a note of caution: I used a standard depth saw, which wasn't deep enough for the angled cut. I had to stop about half way through and cut away part of the plug to allow the cut to finish. It would have been much easier if I could have gotten a deep hole saw.)
Once you are through both sides, you "slide" the exhaust pipe through the hole, cut it to the proper angles and weld it in place. I put slide in quotes because my cuts weren't perfectly lined up (due, I believe, to the problem I mentioned earlier with the saw not being deep enough to cut in one pass) and I had to pound the hell out of the pipe to get it in place. But, when all was said and done, it made for a very nice exhaust pass through. Someday, when I get the car back from the body shop, I hope to pass an exhaust pipe though it!