Does your car lock up outside of cell coverage? I'm not suggesting removing the radios themselves, just the antennas. To the car, it will just always be out of range.
The antenna used for talking to the keys might cause trouble, but those are either inherently short range inductive systems or are receivable using a 20$ RTL SDR to verify it's not sending anything else.
Using Linux with obscure hardware (CNC mills, chromatographs, etc) is a bit like punching yourself in the nuts, but still free.