[TAKPAK]

I would be very concerned about pulling that rig with a 2500 series truck. Last year we bought the 3725 Montana, which has just about the same pin weight as your proposed 3611, around 2800 plus pounds. In reality, the 3725 pin weight wound up being closer to 3200 pounds, and that was before we loaded it for a trip. We had a 2008 GMC K3500 one ton, and have since bought a 2015 GMC K3500 one ton. Yep, same truck, but the difference between the 2008 and 2015 is 1600 pounds of GVWR, and a higher rear axle rating, to name a few. On the 2008, we were over weight on the rear, and the GVWR. On the 2015 we are now under capacity, but not by a whole lot. However, we feel more comfortable with the extra capacity, and the lower liability risk.

Your choice, but airbags only level a rig, extra springs only do the same. Changing those things will NOT increase the truck's overall capacity, nor will it make it stop better, etc.

Your call though, whatever you feel comfortable with.