Flared?

Hey guys, if some one were to ask a question about a muffler such as this:

"are these truly 3 inch or 2 1/2 flared out to fit 3 inch exhaust?"

What does falring the muffler eman? Is this bad? Or is it o for sound/performace?
We'ret alking about Dynomax SUper Turbos here...

I'm thinking they are just referring to adapting a smaller diameter muffler with fittings to mate up to a 3" pipe. If your headers collect into a 3" pipe, then you interrupt it with a 2 1/2 inch muffler, you lose a lot of the benefit of a free flowing system, Especially if you use an under car exhaust since our mufflers are the last thing the exhaust gases run through.