How would you rather get 4" drop up front?
 

I'm weighing some options to end up with a 4/6 drop overall. The rear will likely be a flip kit with relocated shocks and assassin bars.

The front however I haven't decided on the best route yet.

Here's what I'm thinking: 2" drop spindles and then get the ProComp 91-3712 coil over upper strut replacement mount and run a viking true coil over and good springs to achieve the other 2" of drop.

Also, the flip kit setup I've seen has a spring hanger replacement also, is that absolutely required with a flip kit or is it just a means to get it lower than just the flip kit alone? I have 2" shackles already so if that's the case I'd skip hangers and leave the shackles to get the same extra drop.

I flipped my axle with out a "flip kit" I am running a 1" block and that has given me about a 7" rear drop. My old truck, my ECSB, the one in my signature, was a djm flip kit. It is a 4/6 drop. No hanger change, just the saddle style flip. If you are looking at throwing some power at it, a bolt in flip kit doesn't look too sound in my opinion. I just welded new perches under the diff, put it up on top of the leaf spring, and notched and boxed the frame. Caution: this moves the diff forward 1" in the truck, so if you don't want that, be sure to drill a new locator hole in the perch, that moves the diff back 1"

Up front, it depends what you want. my ECSB was stock coils, and the DJM 4" control arms. That truck is soft up front (running a really good stock front shock) I bet that would hook better if the trucks were the same wheel base. Driving my 5/7 drop RCSB around, it bottoms out less, and rides stiffer than my old ECSB.

Check out my build thread in my signature if you'd like to see how i did my rear set up. I think if you call Smith Race Craft and tell them what you are doing they will have the shock, and u bolt plates that you will need to make it all work. I will be adding lugs to my bottom mount plate and running slide a links.

-Kenny

Your plan for the front end would be a nice route to take. I like drop spindles versus drop control arms personally, I've ran both and just prefer a quality spindle. The coil over will make it a nice set up that is easily adjustable versus an adjustable strut with rings that need to be positioned differently.

Wish I could help ya on the flip kit hangers with definite answers but from what I've seen all the flip kits on the market use new hangers. If I remember right my BellTech kit (on my 2013) hangers had two sets of mounting holes to use for a 5" or 6" drop using the stock shackles and for 7" drop use the 6" holes and a 1" drop shackle.