Bassani mid pipes should work with it. You could order two high flow mids and get the stockers cut out, then just put those in and some pipe to close up from were the other cats were. Then take the cats down to the scrap yard and get some of the money spent back.
I have the Bassani hi-flow mids with my silver bullet exhaust. The exhaust shop had trouble making everything fit up right for some reason though. Its worth the sound in my opinion. It will really wake up your silver bullets big time.
IIRC, all the pics I've seen of the factory exhaust, the muffler is dual inlet, dual outlet.... Someone correct me if I'm wrong.
When I bought my truck, the factory exhaust was long gone..