KYB AGX aren't really the best shocks for a race spring or a coilover. They may be able to handle it for a bit but they will wear out more quickly. Need to stick with Koni Sport / Tokico Illumina / Bilstein Sport, really.

JL man, it's different on every car so it's hard to judge a drop solely on finger gap, but I would estimate about a 2 finger gap or so for 1.5" from my experience.