Wow, some more misinformation here. First of all if you are running stock factory seats they do not need to be bolted to the crossbar. That is for aftermarket and fabricated seats. If you are running stock factory seats you don't have to cut the seat cushion for a crotch belt either, you can run it around the front of the seat, an aftermarket or fabbed seat has to go through the seat and be bolted to the floor on a centerline about mid chest of the driver. You will need to cut the seat back if you are using high back bucket seats for the shoulder harness to pass through. Check the stock eliminator rules.
As for the rear down bars you should make them as long as possible to reach back into the trunk (pass through the package shelf) and tie into the rear frame rails as far back as you can. This increases the rigidity of the chassis. I see so many cars with real short rear bars and these guys don't realize they could have done more to strengthen their chassis with very little extra effort. They are just straight pieces of tube so you can buy them seperately as long as you want then cut and fishmouth to fit. Or I'm sure if you call ART, S&W, Alston or whoever you can ask them to cut them longer for a very small additional charge.
I read it on the interweb, it must be true!!
Let's see, Jeep Wranglers have roll bars, some convertibles too. I'm not sure what you're worried about but if you are going to make the statement you should be prepared to elaborate, otherwise you are just trolling.
If the car is that fast you shouldn't be toting around a bunch of people or kids in it anyway. So I'm sure there are some horror stories floating around about how someone would have survived a crash if the cage hadn't been in there but you know what? You can find examples like that with seat belts and air bags too. Should we not wear them? More often than not the car is going to be safer and more structurely sound with a bar or cage in it.