Upgrades to Yamaha 60 TLRA

I have a Yamaha 60 TLRA with a Outboard jets drive for river running. It does OK with 16' boat but.........
Are there any reasonable performance upgrades to this motor to optimize performance ??
Not much else I can do with weight in the boat.

[boats.net]

No there isn't much you can do, it's only about 40hp with jet drive.