So I was probably wrong on the part about the interior, I missed this paragraph on the first read through:
That would mean DMCH could go ahead with the custom interior.As the statutory definition refers specifically to the “body” of the original vehicle, we propose that the interior of the replica vehicle does not need to “resemble” that of the original vehicle. NHTSA believes this approach would allow low-volume manufacturers to update the interiors to provide modern amenities and safety improvements.
Also, this paragraph seems to allow for exceptions to exterior changes (like lowering the front end to a reasonable height) as long as it doesn't have any adverse effects on safetly. I'm assuming minor changes to the height due to lowered suspension would be something that NHTSA would allow and still meet the definition of replica. One could probably argue that the improved handling of the corrected front height would be a safety improvement.
As much as DMCH gets their balls busted around here for the delay, it does suck that they spent so much time and effort into developing a new engine platform only to have the NHTSA guidelines delayed so long that they've now got to start over.Deviations in the appearance of the exterior would be considered carefully. While reasonable allowances would be made to accommodate safety equipment, NHTSA would consider any unjustified exterior changes (e.g., not for safety) as potential indications that the vehicle is not a replica. If a replica manufacturer wants to make deviations to the exterior of the vehicle to accommodate safety features, it would be required to highlight those deviations for NHTSA's consideration.