I'm with Norman on this one.
Cage or no cage I don't think a seven can be considered a safe care compared to say a modern Volvo. No matter what type of protection you add there are accidents that you are not protected against. Cages and rollbars are in themselves a risk in certain types of accidents if you don't drive with a helmet (and possibly even with). Four point harnesses are no good if not properly fastened which I doubt many do on a short road trip. There is no deformation zone on the steering axle (the Westfield one is not allowed here in Sweden for instance, we have to build new ones). Many put seats in that I think, with no evidence to support it, could cut you badly when they crack in an accident.
A cage will protect against more accidents than a rollbar. Potentially it will also cause some injuries that the rollbar would not in other types of accidents. It could also potentially make you feel immortal and make you drive in a way you would not if it wasn't there. One of the best protections out there is probably to be aware that you are probably not as good a driver as you think you are. Especially in traffic.
In the end you have to just decide what type of risk you are willing to accept given looks, convenience, cost etc. If you want a safe car you should walk away.