I bet it would sound like a Zetec with an SVT exhaust. Colter's old car sounded good, not too loud, IIRC, but you could hear a exhaust note.
Strangely, my car is louder then my brothers ZX2. He is running a 40 series Flowmaster on 2.25" piping. I am running a 50 series on the stock stuff. I am sure running without a resonator and having the mystery mod works in my favor.