Runs of the r2 red paper test build enabled me to experiment with airflow through the bodywork. Hacking and covering various inlets and outlets, the optimal combination seemed to be an open nose intake over a splitter, running air under a modified wing-profiled bumper then leading up and out through multiple vents along the forward cowl (essentially the trailing edge of a big forward wing). More overlap down the side of the car between the front fender trailing openings and the leading surfaces of the side pods kept the airflow smooth and controlled past the rear fenders on the way to the wing.
That, plus some aesthetic changes to the windscreen, roof, rear cowl, rear deck, and fenders lead to an effective complete redesign. Also added an additional vent on the right cockpit side to help cool the ESC. Looking pretty sharp now: