All, Well, I asked for it -- and I got it. Again thanks for all the input, however hard it may be for me to take. Really. Meanwhile, I forgot to mention that I am not at all interested in a cosmetic roll bar, so we are talking about function. The ones that I have seen applied, like gerd has indicated, look a bit silly. On the other hand, I am not interested in racing either, so full adherence to this or that safety spec is not part of the picture either. John and I have been exchanging ideas on this, and he says that if he welds in a proper bar structure, you could use it to lift the whole car, no problem. Also, it will stiffen the structure a bit more than the welded frame that is already part of my build. All of that said, once again I am being reminded that the cars are unsafe (being small, light and made out of plastic) and whatever is put in ain't gonna save my sorry ass, even if it works perfectly, and I get on the wrong side (any side) of an SUV hausfrau calling her babysitter to see if it's OK if she is five minutes late picking up the kids cause she's stuck in traffic and can't see my little toy and she is hurrying best as she can -- or some such.
Moreover, I believe that any car that is not literally nailed to the ground can be made to roll over, given the right combination of inital tilt and push. Am I going to flip it over only with steering inputs? Not likely. So let me show you what I thought might -- I say might -- not be so bad. I have pasted a shot of a new Boxter roll bar assembly onto a picture of one of JPS' Speedsters, just to get an idea how something that was done carefully might look. Whaddaya think of this? Now what you see here for the Boxter part is the bars (which are lightly padded), plus the extended seat back, which is the headrestraint. In this view the shape of the bars and the shape of the head restraints are purposefully made to match, so the bars integrate w/ the lines of the Boxter cabin as well as can be. In my (probably faulty) vision, the space inside the bars made for the Speedster would/could be filled w/ a padded insert. As the bar is directly behind the classic Speedster seat, maybe I get some head cushion action. -?- What all this might cost to do has yet to be revealed.
And no, I do not want to buy a Miata; heart is firmly set on a Speedy, plus John already has a good portion of my coin in his account, w/ more to follow, so we are moving out.
Man do I want to get through all this decision sh-- and startt working on something important, like what in the world am I going to have my vanity plate say? So much to think about . . .