01 chevy 4/6 drop ?'s

i just picked up am 01 2wd reg cab chevy 1500. i wan to drop it 4/6 " i have always run isuzus so dont know all i need for this drop.

its an everyday driver so i want the best way. also what size tire should i run an a 20"? i have a set of 285-30-20's now. will these be too wide?

will i need to notch it? any help would be great.