i belive banks does make a bolt on kit for the idi fords, but dont quote me on that. what is all shot on yours? if it needs everything(y pipe back) take it to an exhaust shop and just have em put true duals on with a crossover pipe if possible. 2.5 i belive is the biggest you can go off the manifolds. then step up to 3 inch and run em out the back.

40 series flowmasters sound pretty good on the idi. any glasspack u get will only last about a year, till all the fiberglass material is burnt out of it then u essentialy have a straight pipe. straight pipes sound good but are very load under a load.

this is video of mine. stock y pipe into adapters up to 4 inch with no muffler. 2nd gear to 4th gear WOT. turn up ur sound as loud as u can and it still isnt as load as the truck will be.

http://s138.photobucket.com/albums/q263/coreyzak/?action=view&current=coreystruck014.flv