Rob, I suspect that much of the time since your previous drawing postings has been consumed in the CAD conversion, and that not all that much real design progress has been made--although clearly some has. With that in mind, much of the unsolicited comments below are probably wildly premature but, for what they’re worth:
Structural
Cockpit looks inaccessible--better dummy up a prototype and try getting in and out of it with helmet, firesuit, Hans, gloves, shoes, belts etc. before freezing the design.
Peculiar locations for some braces in the cockpit area.
The CAD model of the frame may give you a file easily accepted by a finite element program--suggest you make use of it, particularly the sections aft of the driver. Looks pretty scary right now. Especially with the upper rails removed.
Frame rail splices--it would be good to verify that the joint mechanisms will, in fact, carry the loads that are expected and be sufficiently rigid and vibration resistant. (That means test results, not just someone saying so). You may want to consider bolted flanges if there is doubt--if they were good enough for Al Teague...
Rear axle bending load reinforcement, as depicted, is completely inadequate. Need to tie one side directly to the other across the top and bottom of the differential housing. See off-road pickup truck type arrangements, or better.
Plumbing
Waste gates?
Intercooler looks to be the classic “too much core depth” and “not enough frontal area” to be particularly efficient.
Consider mounting the turbo(s) lower and more central with a horizontal “updraft” intercooler above them with airflow then exiting directly rearward into the intake plenum. Eliminates a lot of tubing, turns, and heat rejection, and can have more frontal area for the cooler.
Systems
Front wheels to be shrouded or is the area (and any components) in front of foot plate allowed to accumulate salt?
Room in cockpit for pedals, steering gear, fire bottles etc?
Battery over bell housing may not like the heat and vibration and obstructs access to clutch and transmission.
Brakes? On rear wheels or driveline? What kind of differential? Are the flaps going to be absolutely coordinated with each other so as to avoid creating a turning moment? Each of these components could produce a steering bias and since the amount of “side bite” the solid front wheels may have is rather speculative, they bear a good deal of consideration. (Costella rear track is very narrow and has no flaps). Note what, dollars-to-doughnuts, is a steerable front rudder on the American Motors liner pictured previously.
Looking forward to future updates!