This is my 87 with Air Ride Technologies (now Ridetech) suspension. I have single adjustable Shockwaves in the front with the air springs in the rears. When fully aired out, it is about 5-6" lower than stock and my ride height is about the 3" from stock that you desire.
Now airbags aren't cheap but they aren't outrageous either. My entire kit cost me about $2500 and included all the shockwaves, the air springs and new rear shocks, the compressor, air tank, valves, relays, all the hoses, computer, control pad for adjustments in car, and two key fob remotes for adjustments outside of the car.
It is well worth the money IMO and the car rides and handles good. I tried Hotchkiss lowering springs but they didn't get low enough for me. Drop spindles could possibly get you where you want and if you put some lowering springs on, you may achieve your goal.
Good luck and let us know how it turns out.