Rolling backwards in drive it will stall. My GX has done it. My FJC has done it. Driving a buddies FJC in Moab in 2008 it did it. Left foot braking in that situation might have saved it? dunno. Just glad no one was hurt.
Check your VIN for recalls. Most would have been fixed during normal service by the first owner. But you never know. There was a recall for drive shafts for sure. Then have a toyota service center print the service history just to have. (if you have not already)
What do you really want to do with your truck? Rock crawler? Overlander?
1. Remove all the KDSS and go all long travel like Dan's setup. Complicated. Very time consuming.
2. Put your Sport back to stock. Sell it. Buy a non Sport non nav. Remove sway, add your links, finish long travel...
Dan ditched all the factory anti-sway. His never had KDSS. Most recently he added All-Pro's AntiRock rear sway kit. This kept all his flex on the front for off-road. He seems pleased.
Personally, I like KDSS!