The cold air intake will exclude silencing baffles that will make your Mercury slightly louder, but almost noone will notice it. It's not like installing a low restriction exhaust system.
I say do it!
The engine will breath better, resulting in slighly better power and fuel economy. As a bonus, the K&N air filter is permanent. Just wash it and re-oil it twice a year and save the cost of replacing the air filter annually.
