I don't think anyone can say for sure which is the safest without crash testing. You can go based on concept, but in the end, like Joe said, the safest way is a full cage. The full cage bolt in from Porsche is probably the best one.

I have a GMG unit and it seems pretty great.

 

Exactly. On the street, in the mojority of crashes, a roll cage will cause more harm than good (unless wearing a helmet and a full harness).

 

Ok, there seems to be a little terminology confusion here between a rollbar and a rollcage. A rollBAR sits behind the seat (see the GMG bars pictured above), where head contact is virtually impossible. I suppose if you were not wearing a seatbelt, you could come up over the back of the seat in an impact and contact it. In that case you would get what you deserve I suppose. You would likely have a broken neck from snapping over the back top of the seat before you ever hit the bar.

A rollCAGE on the other hand, takes a rollbar type system, and adds front and side protection as well, but also creates and environment where a person's head could easily contact the side or front headbar in an incident. In the case of a rollCAGE, one must absolutely be wearing a harness system and helmet. For this reason, rollCAGES are illegal in street use cars. RollBARS are not.

I am pretty sure the original question pertained to rollBARS

 

From firsthand experience I can testify to that the GMG rollbar is a very nice piece to install and have in the car, especially since it allows the seat to slide back far enough to work well for tall drivers.

 

Right Safety Devices sold through Stable Energies makes a nice full cage that can be welded in to the car while keepin all door interior bits, dashboard, overhead, etc. Some cutting of the carpet is required. Of course, full removal of carpet for install is required. I have one and I paid $2000 some 3 years ago and another $1400 for labor to install.

 

Agree with that. I would not dirve a car with full cage on street whether legal or not.