So I have a YXDL 6.0, the muffler i bought has dual in/out 2.5" PN 12568. One muffler shop says he will install it using stock pipes. Another shop says that muffler will not work, says only dual in/single out will work, 2.5" in/ 3" out, PN 12588. He will cut and block the rear 'Y" pipe to the exhaust tip. There are options for 3" on both. Question is, as I have read on a few posts, either can be done. I do not know if the two make a difference really. Anyone have experience on this? Or am I splitting hairs. Thanks!