I had a large gap on one side with TORs installed. I removed the shield and drilled another hole in the "U" shaped bracket that the mounting bolt goes through. That allowed the shield to be moved closer to the muffler ledge.
ok appreciate the responses; the dealership said they have 4 more with same issue.. they basically said they have it as close it can get no amount of adjustment will lessen it Which i still feel hard to believe
Do what @leatal mentioned. Slot the U shaped bracket which is welded to the exhaust or drill another hole in it so you have a bit of movement on the cover.