if its a bolt in then don't waste your time. if it is a proper thickness and is installed (welded and reinforced) then yes a roll bar could save your life.
Yeah, I looked into getting one for my 'vert. Its kinda scary when you see a car roll over because of an accident and then think, there's nothing really saving you in a convertible.
I clicked to read because I thought the title was funny? I mean are you serious? It would be like asking if pot gives you the munchies and forget what you were saying...
Where was I? Hell I am going to get some funions...... and a pizza..... and water, lotsa water.........
On the street? I'll help righ up until you smack your head on it and it splits your skull wide open. I've bumped my head on mine just getting in and out of the car and it sucks.
The link above shows what happens when you do a shitty job putting one in. If you do a bolt in w/ the right floor plates and use good hardware its better than nothing.