What do we buy?

Looking to purchase a 5th wheel for fulltiming. Towing with a Chevy 2500 Duramax so have to keep within the weight rating whcih is around 15000n lbs. What is the best one to buy?

15000 pounds will have about 3000 pounds on the pin plus the weight of the hitch at around 200-250 pounds and that is a sizeable amount of weight for most three quarter ton pickup payloads. And that is before you put anything else in the truck. I would start with the payload available and then decide what to buy. The problem you may run into is finding a beautiful coach with just the right floor plan and it is heavier than what your truck wants. Fulltimers typically add twice the weight of stuff in the coach as would normally be found in just a recreational fifth wheel used occasionally.

If you want to keep the truck and don't want a smaller fifth, you might be happier in a very nice travel trailer like an Airstream or Arctic Fox. Usually the 2500 series trucks will tow more than they can carry especially the powerful diesels. Many full time in Airstreams and you can spend a quality evening checking that out on the AirForums.