I like mcgaughys. What wheels are you running? I think getting the 16"+ spindles would be best, 2" drop coils then flip kit in the back with stock shackles and a c-notch will give you a 4/6 drop. If you want more all you have to do is pull the 2" coil out and go to a 3" drop coil and rear just install drop shackles and you can get 5/7-5/8 drop. I ran the belltech street performance shocks on mine and loved them. A stiff shock that helps alot with bottoming out but I was around 8" in the rear or 9" when I got my bedcover and i bottomed out a bit in the little c-notch. At 4-6 you wont have very many problems with bottoming out with a good shock and decent roads.
Edit: Typically, its a bit cheaper to keep an eye out for used parts. You can usually find someone that was dropped and then is bagging like I did and you can get the flip kit from them. Spindles you can find if someone is taking drop off to go back to stock or lifting but spindles and flip kits are perfectly fine buying them used. The coils and shocks I would buy new and wouldnt really bother buying a used notch. Dont want it to be cracked from bottoming out or the removal of it.