I have an old set of Flowmaster mufflers on my car that I bought over 20 years ago, before they had fancy names for them. Mine are 2 chamber, offset inlet and outlet. I've never cared for the sound of them, but at the time I bought them, they were the only ones to advertise that they could handle over 400 hp. Now I care less about ultimate power, but am interested in less noise. Overall, I like the sound of Magnaflows. I currently have 2.5" in and out. I think I can fit around a 24" case. What fits our cars?