The 2014-2018 Ram 2500 heavy duty trucks have 5 basic different suspensions that come into play when selecting a lift kit; Diesel or Gas engine, and with rear coil springs or rear air springs and then there is the Power Wagon models. So basically it breaks down to Diesel without rear air, Diesel with rear air, Gas without rear air, Gas with rear air and the Power Wagon
The first two choices are between the Diesel engine and the Gas engine. The basic lifts are the same but they require different front coil springs which will affect the amount of lift that you get. Be sure to select the proper kit so that you get the right amount of lift. The 2 inch levelling kits do not replace the front coil springs so those kits will fit both gas and diesel models.
The second big difference is in the rear suspension, these trucks are available with either a coil spring or an air bag to support the rear suspension. You need to know which option your truck has in order to get the proper parts for the rear of your Ram 2500 lift kit. Once again, if you just want a levelling kit then there is no rear lift so there is only one listing.