I ran an off off-road Mac Prochamber and Flowmaster 10's on my last Mustang (03 3.8, ran 40's, 44's, Magnaflows and the 10's with different midpipes as well). Of the several exhaust setups I went through on it, that one sounded the best by a very large margin. The Prochamber did quite a bit to smooth out the 3.8 even fire tractor sound. I would highly suggest looking into getting one as it will make the single most drastic change in exhaust sound for the better.
In short pick up those 10's off that guy fast! Your basically getting buy one get one free at that price.
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