My 2 cents says stay away from that spa. I see that the cover shows pH damage, which could have damaged more than the cover. There are so many jets you could be in for a large repair on the leak. Spray foam insulation is pretty expensive.
My opinion is I would never buy any other brand used except HotSpring...of course I am biased.
use this advice at your own risk
Pete
http://www.makesmeshutter.comhttp://www.floridahotspring.com