The tech guys are in Cali, so I can help a little for now. 1st, this post should be up in the RCrocs section just above this, it will get proper attention quicker. There is a thread for tech inspection I believe. Anyway..
You can NOT change the frame from the factory. It can not be shortened. Your truck must retain the factory look, including the body/bed. That 3" part of the rules has always been confusing to new people. It actually means the wheelbase can't be plus or minus 3" of stock on any truck. I hope this helps, Kyle will chime in whenever he gets on again.
Cage, there are no set specs, but recommendations would be:
At least 1.5" 120 DOM for high contact areas, 1.75" 120 is the norm.
I am not sure what they would want from you with a Comanche with your doors still on. Without them, I believe you fall into the wrangler rules. You need standard 6 point cage. You need to tie the A and B pillars together on the sides. It's safety, I would be sure to make it strong, with good triangulation.
I hope I helped. Let us know if you have anything else you are unclear about. Welcome to RCRocs, you will have a good time in class 2
