$5,500 is IMO very expensive for a stock Spoiler regardless of condition. You have nothing to lose making a lowball offer, the bass has been listed for over 2 months now with no takers. If your offer isn't accepted and you are not wiling, or able, to pay the asking price move on. There are always over-priced Alembics on Reverb that sit for a long time, much longer than two months in a lot of cases. You would probably be better served trying to find a bass in the states, preferably one you can play before buying or return if you aren't happy with it.
Are you a fan of, or looking for, a five-string with a narrow neck width? I have a medium scale 1978 Series I five-string and have always found it very difficult to play due to the narrow string spacing and I play primarily with a pick. I have watched excellent players struggle to play my bass finger style, it definitely requires getting used to. The B-string is acceptable but has the worst response and feel of any of my five-strings which are all either 35" scale or 34". Not saying that you wouldn't be happy with the Spoiler but paying over $5.000 and shipping from overseas seems unnecessary unless this is exactly the bass you have been looking for and ticks all the boxes for you.
One last tip, never buy a used Alembic without seeing a photo of the electronics cavity... Good luck with your search, once you find a bass the real fun part will begin!