http://www.mazdas247.com/forum/showthread.php?t=79770 The fun starts a few pages later with the cage. Wes has a full out race car, it's sweet. You should make yours like his.
That's a nice roll cage. It's very similar to the one I will be doing for the most part. The main differences are that I have the nascar door bars on both sides for passenger protection (I take passengers with me on track regularly), my rear down bars will go to the top of the rear strut tower instead of the inside and I wont have the horizontal tube from the main hoop to the strut tower. I do like the lateral bar at the bottom of the main hoop and have been thinking of adding one there for my cage as well. Should help a lot in side impact.
I'm surprised I haven't seen anything about that car before.