Im running two magnaflow straight through mufflers and they sound great. Only problem I see with two goo quality aftermarket mufflers is the weight. Twice the weight and each one weighs probably twice what a stock SVT muffler weighs.
warmonger
Former owner of '99 CSVT - Silver #222/2760
356/334 wHP/TQ at 10psi on pump gas!
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'05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red
'06 Mazda5 Touring, 5spd,MTX, Black