Lets see if we can get the basics covered with out writing a book. Your post is very contradicting when you state
"I want it to sit really low, but also I want to be able to bag it to ride normal height" since your opening statement says
" How low can I take my truck, without c notching?!"
So you want it really low on 15" rims, but you plan to bag it so you can raise it up to normal ride height, and do all this with out a C-notch. The short answer is "you can't".
I will help you understand what you can do and you can go from there. You can run 2.5 or 3" lowering spindles up front. You "might" have to trim your A-arms to run the 15" wheels with the 3" spindles depending on what width rim you have.
You can cut one full coil off your stock spring, or add an aftermarket spring for another 2" drop. Thats about as low as you can get up front with out removing the stock bumpstop. If you are running tall tires up front they will need to be exchanged for lower profile tires.
On the rear you can relocate the stock hanger for 1.5-2" drop and add a lower shackle for another 2". If you want more, you can do a flip kit for a 7" drop. You don't have to run a c-notch with a flip, but you will bottom out if you don't.
Absorb that and tell me what you think..
