Speed doesn't worry me, I spent a lot of years doing that with my butt 30mm from the ground.... its the corners that need attention.
Interestingly, the first time I did it I had a 2" lift and shocks were clapped out from a desert run. That made it very floaty and not very tidy at those speeds. When I did it with the 4" lift, the shocks are very stiff and it locked everything down and was quite sedate. There were no brown stains. :D Its not something that is very nice when everything is wallowing around.

