Finished moving yesturday so things are indisorder here, but I think its a 1 1/2" holesaw straight down the back of the muffler. You will need an extension on your drill also. Drill through the 1st plate on each muffler, then start it and see if you like that. This can not be undone.I know they changed mufflers in 11, so I'm going by how I did my 12 Vouager. You have 2 baffle plates in each muffler, then 2 catalitic converters, and one more baffle plate, this one the muffler has to come off for. The one on the left will have to be cut and rewelded, most leave this one in.