The effects are because of the geometry(sp?) change of the driveshafts. It's not a weight thing.

This is something that was posted by Levanen from AE a while ago when some one asked about diff heights:
Raising the diff will result in more onpower traction in the end you raised the diff. For example, putting the front diff to
the highest position and rear diff to the lowest position will give you the most onpower steering and vice versa. I normally
run mine mid low both ends, sometimes mid high in the front. If the driveshafts are straight your car will the more neutral
on and off power. The driveshafts try to straighten out when accelerating which causes the handling effects.

The center of gravitys effect is minimal. The diffs weigh less than 10g. Try taping a 10g lead weight on the topdeck and see
if it makes a difference That is 10x bigger change on the center of gravity than the diffheight and you probably wont be
able to tell a difference.



Hope that helps.