No warranty, $8k is a lot for no warranty. Give you an idea, if I were a Coast dealer, and it was a tub we normally sold for $12k, $7-8k is what I would probably ask for it (3-5 years old) but we would put a new cover, ozone, and circ pump at the minimum.
I'm guessing you need at least a new cover (or expect to replace it in 2 years if it was maintained) and a new filter. Plus the move (pay for a good one... that's a huge freaking spa, protect it!)
I'm not a Coast dealer. I've seen them up close. They look like they are built pretty well. I don't have much experience in reliability. The only thing I will say is the curve is really neat in one sense, but it typically does make ordering covers a pain... and more $$$.
Why did all the lights fail? I imagine they can force the dealer to fix it under warranty before they sell it.
Also... why are they selling it?