Sharkhide. Only way to go.
I have never been pleased with the outcome after using Sharkhide, tried several different times and methods of applying. After taking
HOURS preparing my aluminum for the application, the end result was always disappointing, and dull.
I spent the time polishing because in the end I wanted a mirror finish. Sharkhide may help in the longevity of the finish overall, but what's the point if you are stuck with a finish that looks less than what you know it can?

I have not tried it again in the last couple years so maybe they have come out with a better application process. Wiping it on does not give the results I was looking for with a polished finish. If I started with a non polished finish it would likely never be noticed.
I figured I would hold onto what I had left in case someone came up with a way to thin and spray it, (acetone, thinner) I think that will be the only way to maintain a true polished finish but have not heard of anyone being successful this way.