Hole saw through trailing arm crossmember, safe?

[Reyals Bemus]

I'm converting to an automatic transmission and would like to run a new exhaust system between the frame rails out to the back of the truck. The front crossmember is no longer a problem since it has been removed altogether.

Do you guys think its okay to punch two 3" holes through the trailing arm crossmember? It wouldn't weaken the crossmember enough to be unsafe would it? If anyone has done this before, pictures would be nice!