We have a different muffler... but to show you where I cut the old muffler. Take a look at this:
Legends:
* green area is the stock muffler
* red area is the pipe and up to where it is extended into
* blue line is where I cut the original muffler (again, I did not cut "through" the pipe... just the muffler so the pipe or red area still extends to the partial overlapped green area).
Hope this helps. Sorry if I don't make much sense in my explanations... (not a mechanic myself) :-)