Looking good!
As for the shell, you could probably add a flexible air dam on the front of your truck under the steel bumper and get some of your front end aerodynamics back. I put a conveyor belt air dam on the front end of my 2005 Tacoma, which I use offroad quite a bit, and haven't had an issue. If you hit something, it just pops right back into place. Here is a link to my build thread in case you hadn't seen it.
http://ecomodder.com/forum/showthrea...tml#post438755
Looking at your bumper, If you didn't want to commit to a air dam all the way across, you could do two smaller conveyor belt tire spats mounted to your steel bumper to push the air around your tires, which would also help diminish tire noise and front/rear lift at highway speeds.