The 4” lift and the coil over lift have the same components, except the non coil over lift comes with 4” spacers for the top of the stock struts. So the pricing is 100% in line. I had this kit installed a week ago with the dual speed compression adjusters and couldn’t be happier. I ran 2.5” kings on my 4Runner and they leaked all the time. I rebuilt them 4 times and when I got rid of it, one was leaking again.
also, kings should really only be lifted 2.5” , which puts you .5” over stock height on a trail boss / at4. Once you add rears to that king kit, you’re at about 4k as well. Mind you, those rear shocks from king are much nicer than the standard fox shocks on the rear of the bds kit. If/when fox releases some better rear shocks, I’ll most likely upgrade mine.