The 510 Realm

I'm looking to enlarge the exhaust hole in the rear crossmember. Does anyone have a source for 3"ID 1/8 wall tubing? I don't need more than 4" in length. Exhaust shops here in NYC have pipe, but it is too thin. I did find a source a few months ago, but I would have to buy and ship a few fe...

I have a '72 510 now. Drove a 240Z for 27years. Looks like I have to post here to see forums. I'll be looking for help sourcing 3" ID 1/8" wall pipe for enlarging my crossmember exhaust hole.