Just a little comment, since everyone seems to be dissing the Vortex. (Oh and no, I don't have shares in Maremont...
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I researched the muffler quite a bit before putting it on my car. Its not exotic, but its solid. 14 gauge! steel, painted. Very heavy. I saw a cut-out at my exhaust shop. I believe it won't be rattling anytime soon, judging by the gauge of the flow dividers and the welds. Fiberglass and steel wool filling, plenty of it. The design is very free flowing. The only real restriction is the mating of the square box to the two rear pipes. Some turbulence there for sure. So don't put it in the same league as the super turbos or the cherry bomb turbos. It's not.
Now again, a nice mandrel bent 2.5 inch with a stainless dynomax ultraflow in the resonator position, with no rear muffler, would be the best cat-back system if you were after power only. I'm guessing I sacrificed a few hp (3 or 4?) to get the two rear pipes and the stereo sound. But it was worth it to me. Depends what you want
