what about a roll cage

can you buy a whole roll cage or does it have to be a custom wielding?

You can buy "univeral" cages, but you have to modify them to fit particular applications. Also in most states roll cages are illegal for street use.

I've seen in jc whitney magazine one time,
they had a molded roll cage to fit are car,
the price of it was 299.99

I'll try to look that up somtime.

i'll prolly be getting one custom made for my car sometime. it'll help for when i re-mount the harnesses too :)