Dropped Spindles or Springs?

[Already Gone]

I need some advice cause I'm confused and don't want to ask vendors this question. I want to lower my longbox 72 and after reading nd looking can't figure out whether to use drop spindles or lower coil springs or both in the front. Some people do both and some just one or the other. Can someone tell me the pros and cons of using either or both. I have a big block in the truck and want to drop it 2" or 2 1/2" in the front and 4" or 5" in the rear. I will probably get the parts from ECE in Fresno as I've already bought some stuff from them and like the way they deal. I will be running P235/70R15's on Chevy 15X8 rims all the way around to start. The plan is to eventualy go to P255/60R17's in the front and P275/60R17's in the rear.