I'd recommend a letter. It takes only a few minutes to send out. My letter, short and to the point:
Dear ____,
Can you please ensure the continued availability of Toyota Marine Sports parts for Toyota Epic boats? We bought these boats in good faith and want Toyota to ensure future availability of parts.
Sincerely,
___________
It is an effective letter. I've already received two responses from Toyota. In addition to the two addresses provided earlier in this thread, also send a letter to: Mr. Ken Elliot at Ken_Elliot@Toyota.com. Mr. Elliot is National Manager or North American Procurement Operations. He is aware of the situation and is investigating the status of everything.
Toyota no longer owns the parts. They were sold to a third party long ago. Mr. Elliot is investigating the status of the parts and where things stand today.
In his conversation with me, he asked, "What do you want to accomplish?" I told him, ideally, continued availability of all parts if possible and, at a minimum, continued availability of the parts that are Toyota specific and the failure of which would cause us trouble with our boats.