If yor dropping your EF down be a bit carefull, If your using kingspring superlows, this will tilt your rear axle/diff on to much off an angle, this will put the stress on your driveshaft and in time bugger your transmision output shaft bearing. If your EF is a XR6 or 8 however, you should be able to adjust that angle on the rear axle/suspension set up.
Ive got an EF Futura, was going to drop it on superlows untill i spoke to a number of people that have had this problem. I ended up using springs from a EL XR8 and shocks from a AU2 XR8, made a HUGE difference in handling, and looks good too. For some reason though when i compare the height to a XR8, mine seems a bit lower too, i thought it would be the same. Well worth it.