It is understandable that you would not hear back as no manufacturer wants to comment on anything outside of the ordinary use of a vehicle in case something bad should happen.
Even basic changes like replacing a radio is no longer a simple change with today's vehicles. I have asked easy questions like switching tires or adding driving lights and have been told "we do not recommend changing anything from the manufacturers specs".
Good luck on getting any commitment from any company today, the lawyers have made it clear they cannot reply.
