I agree...a lot of guys cut their springs and don't have problems (right away) but it's like piecing together a CAI out of PVC and putting in your engine bay, yah it works but the right way is simply better
Plus as said progressive springs, as well as any spring have a preset load. Once you start cutting off coil, you change that load rate...obviously with less coil for the load to be distributed thru you're creating more stress on the remainder of the spring, which can cause more sagging, squeaking and worst case, a destroyed spring.
Taking out your iso's will lower the car some more...probably ~.5" if you take out both the top and bottom isos. I'd try that, let the car settle for a week or 2 then decide whether it's dropped enough.
12 Black GT500 SVT PP l 2.6 Pulley/Idler l Airaid l o/r X l 305 NT555R's l Recaros l
04 Azure Blue Mach 1 / 03 Sonic Blue 3.8 / 14 Sterling Grey F150 FX4 402A 5.0 / 11 GT500 R.I.P.