Has anyone had experiance with the OEM mufflers that have been modified and are on Ebay. These are selling by under the name of Stage 1 , Stage 2 and Stage 3 . Each has a slight difference in tone. Another sells by the name max 1, max 2 and max 3. they are new dealer take offs and have been modified. Each say that the 1's and 2's can be ran with no other changes(a/c, remap) however the 3's need the a/c and remap. I would appreciate any comments.