So I have decided to do the borla xr1 muffler on my single 4 inch. I can fit the round or the oval case. The oval is xr1 sportsman. The round is xr1 multicore.

Anyone have experience with each?

 

I have the XR1 round case on mine. I ran the Flowmaster merge off my ORY with a little 9" Dynomax mini bullet and then the XR1. A turndown welded right to the XR1 exits perfect at the rear axle. The sound of the two bullets is nice and deep too with no rasp.

 

oval case is quieter and has a better tone. Round is loud.