m20b25 dual piping, converting to single

[alex1987e30]

hi r3v i just got a Ansa muffler at the junk yard the other day. once i got it and paid for it i was at home about to throw it on. then i noticed it was a single piping. and my 1987 bmw 325IC 4/87 is dual piping after the cat. what would happen if i converted it. would i gain more power or loose any? or stay same would it be quiet or loud?
please help thanks alex

[MR 325]

What size is the inlet on the muffler you bought? When running single piping on a M20 I prefer to use 2.5" but 2.25" would probably be enough for a stock 2.5L. You're not likely to notice any change in performance either way.

[ArdaMK2]

What about a "Y pipe" after the muffler? Would that work. Im having the same issue