Damn, wish I had known about the Moeller tubes, seems like they would have been easier. I used the McMaster Carr pipe on my 2003 330, Grady told me 1.25 inch x 3.5". I followed imjus4u2nv's advice and went to 3 5/8" for the length, custom cutting each one. I didn't know how to use Willy-C's tool so I just flared both ends at once in the hole. The tube self-centered and the flares came out great.
Getting the old ones out was a bit hairy, followed the advice of others and hammered them out with a screw driver. I did it from the outside and once I got the old tubes crunched up in the middle, pushed them through with a bolt and hammer.