is it worth it to change from the stock tail pipe section to a 3" piece??
the stock over axle looks to be about 2.5" or 2.75"
this is with a aftermarket muffler of course

 

I think the stock dia is 2.75. Not sure how much of a difference it will make performance wise, but it will make it easier for you to find a nice stainless or chrome tip to fit a 3" pipe as opposed to 2.75" I would think. (I noticed in your other thread that you're looking for a tip also)

 

yes, the stock is 2.75 at the tip, but if you look where it is just about to go over the axle, it necks down to i bet 2.5 going over and into the stock muffler.
am I correct on assuming that 2.5" tail pipe isnt going to hurt a stock motor 5.3 at all as far as power goes.

 

I would considering my SS catback is 3"

 

for the mods you have it would be best to leave the stock tail pipe and put a performance muffler in place of the stock one.