Lightening an E34 isnt worth it in a performance standpoint.
If you have a particular purpose in mind then you can work towards that.
lighten it say 300 lbas, the car would probably loose it in a turn unexpectedly beacause this car was made and tuned for the weight that it is.
The stiffness of the body is amazing! Last week I was changing the trans filter and I bumped the rear stand ans it was loose, I mean take it out loose, my friend could not believe how stiff the car was. Thats when we started talkin about replacing the Regal with one of these. Less tubing to tie it all in = lighter and just go basic NHRA/IHRA ruling with chrome moly instead of steel and add a hundred pounds and the 632. the 50/50 weight would be appx 65-35 to the front which is a LOT better than the Regals 20 rear weight.
I should shut up I cant afford it and im just Geeked at the thought.