Stock exhaust pipe diameter?

So I picked up a borla pxs muffler. I'm trying to figure out the best way to install it. The inlets are 2.5'' but the outlets looks to be 2.75''. Are those numbers correct? My plan so far is to cut out the stock muffler, the rear cat and replace with the new muffler with the extra pipe welded on to make up the space from the cat delet. Any one see any issues with this? I'm a decent welder but this will be my experience on exhausts. Any tips are weclome

 

I don't see any problem. I did the same thing on mine.

 

Nice ... what muffler did you get?

 

It's a magnaflow and its not very loud until it gets at like 4000 rpm... I should've gotten a dual exhaust to be a little louder lol

 

The guy I bought my borla off of said it was too loud for hI'm and that he must be getting old