Great deal for anyone looking for some....I bought a case from them already and it came within a few days....Yep, Fluid Film is awesome- great protection. On my VXR (which would get the inside of the hulls sprayed down each ride) I would spray Fluid Film in there. Prevents corrosion, makes the plastic shiny, just all around good stuff. Downside is its kind of hard to find.
As for the Spark, which from what I have been seeing, the inside of the hull is pretty well sealed so once a year application may work out.