I doubt you will get many responses to this question. Mine and Bill's cars are the only TR's I know of with cages. I have built nearly all of the roll bars for the TR's in this area (7-8 of them) Give me a call at (321)626-2008. I can get you a cage and have it certified at the same time.
I have been custom making them. The kits I have seen, fit like $h!t. All the GN rollbars I have done have been chrome-moly to save weight. This means they have to be tigged. Total weight with removable side bar is 34 lbs. I am trying to get out of this business because I don't make any money doing it.
I finally found a chasis man that I am very happy with and am trying to stear this kind of work towards him. He custom bends everything and I haven't seen anything that he can't do. His rates are reasonable and he works very quickly (suprising for a chasis shop). Here's his website: http://www.theracecarfactory.com/