A little scoop was added over the ventilation intake vent on the right side below the engine intake vent. These are just vents at the rear of the passenger compartment that allows the interior air to flow through the cabin and exhaust out the back. This should improve cooling and defrosting performance. On the topic of defrosting, a heated windshield becomes an option. The extra thin heating wires run vertically and are barely noticeable.
Reports are that it works wonderfully and can be retrofitted to older vehicles.
I don't know exactly what this involves beyond the scupper valves and intake scoop. I believe that the main blower was redesigned. The rear AC vents were moved also. The sliding rear window becomes standard on 2 and 4 door hard tops. For example, the headliner is now padded instead of being just rigid plastic and damping material was added under the dash.