Dont know for sure on a Yamaha ,but upgrading my Mercury from a 150 was cost prohibitive .
On the Merc the controls had to change from analog to digital .After the labor cost it would have been less to buy a new boat .
Even if I switched to Yamaha the controls would still have to be changed .
So my boat will go in the water this weekend (damn Wisconsin weather). I would like to decide this week if I am going to do the re flash. I've heard from one person that did have pre and post numbers that did not have much of a top end boost. Is there anybody else out there that has these numbers and demonstrated a significant bump? I have the 225 Vmax SHO and was told I would be at 300.