cage advice..?
If you are planning on racing the car at a certain track, say an NHRA track, you should get a rule book from them so your cage will be legal as far as they are concerned. If a car runs slower than 11.50 and it has the stock firewall and floor then it does not require a roll bar as far as NHRA is concerned so you can do just about anything you want with the roll bar / cage.
Chuck