You will be fine with your towing setup.
Your 2500HD can handle it. You'll like the Sabre. I've got a 31RKTS and besides the Concertone, have had no major problems.
With your long bed, you won't even need a slider hitch which will save you a few bucks.
Good luck with your Sabre, if you decide to get it.
2013 Palomino Columbus 320RS
2007 Dodge RAM 2500 6.7 Cummins
Reese 15K manual slider
M.I.L. in Florida for good!!