Unless its a jet ski that car wont have any pickup with a boat attached. The turbo will kill what little low end torque the car had to begin with. If its a manual transmission, you can ride the clutch a bit while holding the gas down to get it the power you need for it to move but that will end up frying your clutch soon. If you want to pull a boat I'd recommend that you spend the money that you would pay for a turbo on an old ass f-150 or something and be done with it.