I agree, Cage is not safe at all on the street same with a roll bar for that matter. You would have a tough time getting insurance with some companies and those that due will have a tough time when it comes to a claim.
besides subframe connectors add some fender to core support bars from a 1st or 2nd gen camaro...even GM G-bodies will work..can do junkyard route or aftermarket make a pair of X bars behind rear seat make sure you have a engine belly bar or make something similar but make it triangulate into bottom of rad support can make X tubes for the actual rad support aftermarket monte carlo and export bar from Toppranger