Dinan are very good as well as Eisenmann and Remus....For are really deep growl you may want to consider the Eisenmann Race or the Dinan. The Reumus are also very good for a nice sound and cheaper on the pocket....

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2004 4.4i Titanium Silver
Eisenmann Race Exhaust
Sirius/Nav/BT/Aux/DSP
4.8 Body Kit (Rear only so far)
ACS Pedals
Aluminum Running Boards
DINAN High FLow CAI
20" Style 87's