roll bar vs. roll cage

Here are some weights per foot of MS and CM

Mild Steel .134 Wall D.O.M.
1 3/4 = 2.31lb 1 5/8 = 2.13lb 1 1/4 = 1.60lb

4130 Chrome Moly .083 Wall
1 3/4 = 1.47lb 1 5/8 = 1.37lb 1 1/4 = 1.03lb

4130 Chrome Moly .065 Wall
1 1/4 = .82lb

A normal 6 point bar has about 25-30' of tube and about 5' of crossbar in it. You save about 20-30# with cm and a lot more $ for material and install. CM can not be mig welded per NHRA.