Comfort wise, stock Raptor rocks. The Raptor I had at TRR is my daily driver. I upgraded from the stock shocks because I got a killer deal on the Kings, Outlaw Raptor Bump Stop and Tie Rods. After selling the stock shocks, I paid 2750.00 including installation for all of it. For my usage which is parking blocks, curbs, speed bumps and highway, the Kings were a serious improvement over stock. TRR was the first time that the truck had seen the dirt. The aftermarket shocks made a difference in just the daily driving on the roads. It was more comfortable (Lexus smooth) to drive over every day obstacles like bumps in the road (Miata's/Prius's) and railroad tracks. Was it worth the investment to me? Yes. Now that I actually hit the dirt with that truck, damn, it was a huge improvement over stock. I wasn't passed once and passed everyone in front of me. Having beaten the shit out of my other Raptor and knowing what the breaking points were on the truck, what it could and couldn't do and knowing what my driving ability is, I took my truck to 8/10 of ability. I had a blast, truck is fine minus the skid plate (which I have the stock one from the other Raptor) and a cracked windshield. When I end up with another Raptor in 2014/2015, I already know what upgrades I am doing right off. Suspension and I'll probably try out the Icon's for that.
As for a stock GT500 on the track
It needs all the help it can get as they can't turn a corner without mods.