The first MT full cages had a different rear section, that’s seen on the opening page of my web site. www.metaltech4x4.com (That’s me climbing Rusty Nail in Moab) I switched to the hoop style in the rear since it made for more room in the back of the truck. It is also faster for the installer to build the kit as well. The C pillar has that kick inward for a number of reasons. #1 is the clear the soft tops as they stretch inward compared to a hard top. (Soft tops are smaller than a hard top) And as ALF pointed out this lets the C pillar be placed further back for more passenger room. Ok its style points too. If you look at the cage from the top the C pillar is about 2" narrower on each side than the B pillar. Again this was to make more room for the passengers yet still allow the fully built cage to be removed from the truck. Since the Profile design fits so tight up to the dash you have to slide the cage back a few inches to get it out. Since the tub has the large radius in the corners, mounts quickly hit in the inside under the corners if they are straight. This is why the most current mounts that come with the full kits are laser cut to match the radius of the tubs and step over the C pillar mounting area allowing it to be so far back in the tub. (yet still be able to pull the cage!)
Mark
Mark