Congrats on buying the best damn truck on the planet!
Hit the HD forums for info, but there are a number of things you should consider.
First, the intake sucks. Either cut a hole in the bottom of it and put a K&N panel filter in it or get an aftermarket intake like an Air Force One or something similar. (I have the AF1 and love it).
I got more than a pound more of boost just by letting the truck breathe better.
I put a 4lb JDM lower, superchip, breather cap, and AF1 intake on my truck. It really woke it up! Mike Troyer can hook you up with the chip, and AF1, and he is also able to sell JDM parts. Look him up on the board here. I think he is superchips_distributor or something along those lines. (he hangs out in the chip forum). He will really take care of you and owns an L, so he knows your motor.
I am headed for a BABOLT throttle body next... It is quite a work of art. Accufab makes one, too, but I like the custom look of BABOLTs TB as he will etch a logo that goes with your truck on top of it.
if you wanna see that little gem.
good luck and email me if you have any specific questions...