The Flowmasters flow much better than the stock BDR mufflers having only two 7/8" perforated holes...
They do come unpolished so plan on spend some time sanding and buffing
And they are a bit larger ID than OD of the pipes. I took mine to a muffler shop and had forward pipe and tail spouts expanded a bit. (Don't push it they can crack) You won't get a perfect slip fit but the welds won't be enormous.
Ensure you install the muffler with the short depth cone on the inlet.
https://www.youtube.com/watch?v=Xuww8Yjyzsk
While your at it you may want to change the rubber support mounts. Bosal PN 255-481 $2.00 per most everywhere.
I added a hose clamp around the mount. Just snug enough to keep it in place and reinforce the mount from tearing.
Sound data from a earlier thread
need sidepipe options to get the decibel level down
Last thing: These are 1/2" larger OD than stock and the heat shields won't fit without re-contouring and larger clamps. They run a lot cooler with the Ceramic insulation in the case but my wife still got a pretty good Snake bite getting out of the car...