Thank you. Forgive my ignorance, but what is FTG?
Just learned this one myself while trying to find a way to compare ride heights between cars of same make. I put the end of a tape on the ground next to wheel center and measure up 90 degrees to the highest point of fender lip over wheel. turns out that is called FTG by the cognoscenti. I use inches.
Not a perfect comparison but useful to note when trying to compare suspension setups. I am a little lower than stock right now on stock size wheels/tires, posted my FTG's on here somewhere recently, I will try to find it and link.
Edit: The other thread is Adjustable ride heights, no mouse to copy link with. Also, my FTG is 23.75" F and 24" R.
Sekred posted a link in that thread to Eibach springs that says OEM ride height is 13.4" F and R measured from center of wheel. Sekred and Jerrick of MeisterR both say better to use center of wheel to fender measurement so that wheel/tire variations are taken out of it.
So subtracting my current well worn OEM wheel/tire dimensions, my current wheel center to fender measurement should be 12.1" F and 12.3" R. Between 1.3 and 1.1" lower than stock. Probably a good place to stop and see how it behaves on track before more lowering.