68 C-10 exhaust going through frame crossmember question

[dubs68SWB]

I have a little C-10 that I'm getting ready to do the exhaust on. I posted a question awhile back for you guys to show me your exhaust and it seemed like most of you made 2 holes on each side of the crossmember that the rearend trailing arms attach to. My question is whether or not it's neccesary to re-enforce the crossmember once you have made the 2 holes. It seems like most of you welded in 4" steel pipe and ran the exhaust through that. I think that would be easy if the cab was off the frame, but my truck only has the bed off and there is not much room. I just don't know how much force is put on that and whether or not it's a must to weld some kind of support in there. Please let me know. Thanks!!!