Q? for Jon: DSII: Grav Vehicles

Hello, I have a couple questions for Jon Tuffely:

In StarGrunts II the book says that Grav Vehicles can enter combat in Low
Mode. In Dirtside II we never hear about the difference between them. How
high off the ground does a Grav/Repulsor vehicle operate?  Or was there
a mix up VTOL craft? Grav Vehicles do operate at a certain hieght off the
ground, can they
conduct a pop-up maneuver in DirtSide II (for example at 1 level of
altidude)? Can this be replicated in StarGrunts? How would you do this?
        Because Walker Vehicles have a +1 on their apparent size, I'm
assuming it is for their height in the legs, can they peer over things? For my
size 7 Imperial ATATs (apparent size 8) they are 1.5 height levels tall. We
allow them to do "Hull Down" attacks behind low hills and tall buildings. I
think that these vehicles should also be able to crouch behind terrain. Of
course when they do this they cannot move... Any thoughts on this? Phil P.