I just picked up on the the mufflers from John and George at Top Speed and here's what the discrepancy looks like before putting it on the car:
That's a stack of 6 business cards under the right tip.
Here's a measurement at 1/8th to 3/16ths difference, sorry that I couldn't level the tape:
The welds look pretty good too:
When I mount it on the car, if someone is close enough to notice that 3/16th's difference, I'll just wave them past because they're too close to me.
The appearance is completely insignificant, I can't wait to hear it wail at the track this weekend!