Anything from mcgaughys or belltech are really good parts, there are several ways you could set up the front suspension for 4" drop..
2" coils and 2" spindles
2" spindles and belltech drop struts set at 2"
4" lower control arms
You would have to pm some of these guys running 4/7 on nnbs and see what rides the best
Word. Tim is extremely helpful, just give him a call and he'll get you set up if you want McG....if you want the 4" arms then call NorCal and he'll get you hooked up.
I have a 08 sierra 4 door and have the belltech #647sp kit. It is a 4/6 drop, if you do a 4/7 your front will be 1 to 1.5 inches higher then the rear. 7 inches in the rear will be cutting it close without a notch, I have about 2.5 to 3 inches from rearend housing to frame. If you have any questions bro, feel free to PM me.