For my model year, the Ram 2500 and 3500 only had a few differences. One was the rear springs. I solved that with airbags and then adding a superspring to the rear. The second difference was wheels and tires. As I explained before that was a big issue. The 2500 had 17 inch wheels. There are currently no tires available with more than 3200 pound load capacity. In addition to springs and wheels/tires, you need to consider adding high performance shocks. You might also want to consider a sway bar. I have not added one, but some others find they help. It is something to consider after the other upgrades.
I have never heard of any issues with insurance nor with law enforcement.