Which Bilstein adjustable leveling shock

2500's have different suspension. You can put Bilsteins shocks on it but they aren't going to level the truck. For that you need either taller front coils or leveling spacers. You'll want to put longer shocks on at the same time to maintain the ride quality. Depending on how much you lift the front you'll probably want an adjustable track bar too.

As far as exhaust goes, does your truck have a hemi or Cummins?

Okay then I'd take a look at Flowmaster or Magnaflows websites to look for cat back kits for your truck.

A track bar centres the front diff under the truck but connecting it to the frame. When you lift the front end the stock track bar is essentially too short and the diff will be shifted to e drivers side of the truck. An adjustable track bar can be lengthened or fix that.

Yes, leveling or lifting above what a lift kit is designed for is when the adjustable track bar is required. Essentially it should be put on if the suspension is modified at all. I'm running a BDS 8" lift which came with a track bar drop bracket which should have recentered the axle correctly. It didn't, not enough of a drop... So I plan on buying an adjustable track bar to get it all setup properly. It also helps tighten up the front end and make the truck handle better.