If you're mechancially inclined why not switch to disc brakes? You'll have a better brake that will last a lot longer than the drums with the washdown system installed? Price wouldn't be too much more..

On the other hand, an extra 5-minutes or so with the garden hose will render about the same results as the flush system IMO. If you hit the salt a lot in 5-years you will probably need major brake work anyways.

Just my .02 cents.