I STRONGLY recommend Magnaflow. It has the best exhaust tone.
Here is a list of the exhaust systems I tried on my truck.
1> Stock exhaust manifolds, 2.25" pipe, dual cats into single 3" pipe stock muffler and resonator
2> Dual 2.5" pipe after stock cats into dual flowmaster 50 series, dual 2.5" pipe out the back
3> Pace Setter Long tube headers, no cats, purple hornies glass packs no pipe between glass packs and headers or after glass packs
4> same as above but run dual 3" pipe out to passenger side right before rear tire, locate glass packs to under passenger seat :-)
5> same as above but replace glass packs with magnaflow.
http://www.magnaflow.com/
Jeff