Wayne,
One thing about the gen2 4.6L is. Being multi-valve it is a deep breather. The 3 and 4 valve versions develop the best power across RPM's, with long tube headers and duels. Of coarse there are no headers for the trac.
My issue is with a V8 though, is. The true V8 sound with true duels, and the couple extra HP & TQ. Providing using the right size tubing, and mufflers. Im old school....LOL
If I had a V8 I would have to duel it. Just me. You will get good sound and a little oomph with single magna-flow kit. Anything beats OEM...LOL