Maybe the center of mass is below the axles - that would explain it.

That makes perfect sense... but it never would have occurred to me in a million years! I bow to your excellent analytical thinking! Thank you!

Update: I changed the model but front end still lifts upon braking

perhaps this error is significant?

00:34.188 INFO: Uploading package to GPU "patmarrnc/REDCAR_BLENDER"...

00:34.202 ERROR: center of mass clamped to the object's bounding box, from: x=0.054754, y=-0.053339, z=1.169973 to: x=0.054754, y=-0.053339, z=1.145915

05:21.046 ERROR: center of mass clamped to the object's bounding box, from: x=0.054754, y=-0.053339, z=1.169973 to: x=0.054754, y=-0.053339, z=1.145915

07:22.834 ERROR: center of mass clamped to the object's bounding box, from: x=0.054754, y=-0.053339, z=1.169973 to: x=0.054754, y=-0.053339, z=1.145915

08:48.147 ERROR: center of mass clamped to the object's bounding box, from: x=0.054754, y=-0.053339, z=1.169973 to: x=0.054754, y=-0.053339, z=1.145915