I don't know if a full cage (custom or otherwise) would fit with a stock, full interior. That said, I had a full custom cage welded into my car. My friend tucked it into the A pillars and roof as much as humanly possible (because I'm driving it on the street and the plan is for track days (HPDE not wheel to wheel). My interior isn't stock. If you go this route, get yourself a wink mirror so you can see all around you. The first dash I fit into the car I had to chop the ends off. It looked crappy, so on the second one, I carved out the foam and metal frame from the ends and fit it around the A bars...I think it turned out pretty good. I lowered the seat mounts a good 3" to give myself more head/helmet room. If you install a roll bar or cage, your rear seats will be useless and should be removed, no one will be sitting there anyway. Make sure you set it up (measurements) with your interior handles/window cranks to make sure you have enough room to use them. Good luck, be safe.