Buy a Corvette/350Z/Viper/<Place ANY sports car here> .....
Well, since you already have one, you could always go for front/rear sway bars. Stillen has a package and Hellwig is a good brand. Don't skimp on tires either. The Pirelli Scorpions handle like a dream on my truck!
I like my front and rear Stillen Swaybars. Holds unbelievaly well, considering it is a truck. I've taken 45 mph curves at 80, comfortably, don't recommend that of course, just had to try it once.It is a much safer truck now.
Some low-profile tricks from an old hotrodder - these won't get you noticed by the local constabulary, but will get you some serious wicked handling changes:
Change down the tires to 60-series; good wide stiff street tires, if you're not going to be hauling anything. If you've got 18-inch wheels, get a set of 17-inch and do this to it. This will effectively lower the truck about an inch or so without having to put a kit on it, plus you can get it right back to load hauling with just a wheel swap.
Then change out the shocks to a good set; I had good luck with Tokicos when I was hotrodding and burning up the back roads. You want to get to talk to a Rep if you can, and ask him what to spec that has great snubbing action for your truck. You want rebound control on a vehicle this heavy - this will give you great control.
The sway bar thing is great to do if you have the bux left over from these mods.
Also, get it painted Deepwater Blue if it isn't already. Deepwater is the sneakiest color, also the fastest around corners...