ABout the only thing I seen was a sound differnece when I had a Y pipe On mine But I liked the Duals Much better and Like the dual looks out the back. As for the Over all STREET performance I realy didn't see any difference There. I had a 2 1/2 collector Y to a 3in single. Duals were 2 1/2s to a 2 1/2in turbo Mufflers with a 2in out let with turn downs just before the rear axle.
The Y should be bigger On the Out going side to keep the same flow as Being a dual. If it is the same size as the Incoming It would make more back pressure and be less effective then the duals themself. And down size after the muffler to keep the Heat. (As the exhaust cools It also becomes slower) This is something I once heard How true it is I have No Clue.
So the Question(could be?) is do you want to spend the Bucks For 2 of each Or just one. thats is up to you.
God doesn't like ugly.
