Hi Sue.
Sorry for the delayed response:
Well......Stock for the REAR on 18's with 255's (which is what I have now) is 33 1/2 Inches.
For the FRONT, I turned the bolts exactly 6 revolutions to reach 33 1/2.
I raised front less than 2 inches to get her level with the rear; therefore, stock front height must have been around 31.5 - 32 inches (with my 255 18 tires).
Hope that makes sense.
Maybe someone who still has the oem 245 tires and 18 inch wheels will go measure and tell us for sure.
As for "unwinding" them too far:
Yes....you can go past the factory setting, which would lower the vehicle.
At least, I am assuming this can be done on the VX.
(I have lowered trucks in the past by turning the torsion bar bolt counterclockwise.)
GPA