Well, what I thought was "obvious", may not be. I replaced my exhaust system and was all set to put the entry into my aircraft logbook when a helpful neighbor opined that it belonged in the engine logbook.
To me, the exhaust system is peculiar to the air frame and if/when I replace the engine, the exhaust system will probably stay with the aircraft while the engine gets exchanged.
To my neighbor, it is part of the power-plant and needs to go into the engine logbook.
After consulting the high priest of all knowledge (Google), I found that there is some controversy and that it probably doesn't matter from a legal standpoint.
However, I want a correct answer, so I am asking Mooneyspace....which logbook?