I just recently got 2.25" piping on my EX coupe. Is the flangs on the stock EX muffler the same as the stock SI muffler? I want to put an SI muffler on my car.

Do you already have the Si muffler?

If not you should just get something like the Apexi N1 etc

I've considered those. I just don't have the money right now. I want the Mugen Twin loop exhaust. But anyway, I heard that the Si or GSR mufflers etc have a higher flow than my EX. With the piping i have, my car sounds like a tin can. A friend of mine told me that I should get something with a higher flow, like a stock Si, or GSR or something. I'll try it if i can get one cheap. I'm still rather new to this, I would appreciate opinions. thanks.