Spindles, control arms, or both

do you need drop spindles or control arms if you are going to bag the truck, or would both make a differance?
are there any (factory) rims that will bolt up with out having to grind tabs?
is there another rearend setup besides a four link and panhard?

You can bag on stock spindles and control arms. For factory rims, I don't believe any over 16" will bolt up with out modification.

There are many types of rear end set ups

3 - Link
2 - Link(Mentioning this set up might start a debate)
Ladder Bar(Similar to 2 Link, popular among drag racers)

Parallel 4 Link with Panhard
Parallel 4 Link with Watts Link

and y-link,the x-link, the no-no 50/50 link

Triangulated 4 link, reversed 4 link, 4 link w reversed uppers, 5 link, the list goes on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on and on!!! You get the idea, lol!

You don't NEED drop spindles, but it sure makes life easier. I didn't use them, but I had to pocket the frame because the angle of the bag was so extreme. I like the sick negative camber without drop spindles, but it will wear through tires faster.