new 540s vs old 525s
 

Hi guys, I'm purchasing a boat that has new Merc 540s. I was curious if Merc addressed the 525s top end service issues that people speak of in the new 540s. How different are the newer engines internally?

As I've been told, the 540 is drive by wire on the shifting. Is that correct?

Does anyone know what the difference is between the 540 and the 565? Induction difference only or is the calibration different as well. Can an existing 540 be updated to a 565?

Thanks in advance and appreciate any feedback.