Rockerboxes, Windsheild Frame, Firewall are 3 pretty major ones

*Doors are the same as P/U's, just have to cut them down to fit.
*Single walls are more desireable, they bolt from the top down &
have dome lights in them, value of them is 3x that of the double.
*Roll bars where optional, the OE looking ones are harder to find.
Hope this helps as I'm sure others will respond with much more