I run my 2016 Z21 between 40-50 on a regular basis, especially when my wife is with me. I do not have porpoising problem I trim it up some to free up the motor and still no problem. The time I have a problem with is when I start to come off pad and the motor is still trimmed up. I think its a matter of finding where your boat likes to run with the payload that you have at the time.