2.5 Muffler question

My buddy got a Borla muffler put on 2 weeks ago sounds great but after looking at it further I realized that he bought a 2.5in instead if the 2.25in. I know 2.5 would be fine but his outlet pipe is still a 2.25, is this something that can hurt anything or should he just not sweat it. So just to clarify what im saying, the inlet and outlet on the muffler are 2.5in. thanks.
Long time reader first time thread writer.

 

Huh?

 

It's not a problem at all. Lots of people running 2.5 mufflers on the 2.25 piping, me included, and its even a Borla. Actually makes installs easier as the muffler piping slips over the stock piping so it can be welded on.

 

didnt think it would be a big deal but just makin sure. Thanks for the input.

 

I'm Runner the same Borla Pro XS for the last year working great