The proper way to lower the rear of the truck is to buy the kit from Belltech.
You could get the leaf spring pack from Maxtrac/Springtech that lowers it 3-3.5" and keep your drop shackle but i can tell you now that it will ride like crap. You will have 3/4" of up travel before the bump stop touches.
So you would recommend the Belltech kit? What about the Mcaughy drop kit? I need to do bags or something as well so I can still load the bed. Any help would be great! Thanks.
I can tell ya that the two existing helper bag setups (Airlift and Firestone) will not be a good option to use with a McGaugheys or doing the remove a leaf mod. It will ride like a tank and be unbearable.
With a flip kit, you'd be forced to fab a one-off helper bag setup. Sounds expensive... Maybe look into one of those four-link jobbies. I have no idea what they are, but I've heard it's the only way to do a legit drop in the rear and keep any kind of payload capacity/ride comfort.
I have the PRG flip kit on my T with the air lift helper bag kit it rides and drives great i also tow a 16' enclosed trailer weighing about 6000 with out bottoming out once. here is a pic of the instal