Mateo,
Everyone has already covered your questions quite well but I'll add a few points and add my 2-cents to others.
Areo 8s IMHO look better in metallic colours - they show the curves and therefore the lines of the car far better than a non-metallic.
With 550 miles on the clock, it hasn't really been driven. Therefore, I would suggest booking a night in a hotel so that you can collect the car early on day 1, drive it extensively on the first day and bring it back to the garage on day 2 to have any fettling required done. No one knows these cars as well as a Morgan dealer and simple things like rattles, squeaks, door alignment, etc, can be done quickly and easily, if the mechanic knows the car. Furthermore, sit in the car and get them to spray the roof with a hose to simulate rain - not a pressure washer, just a garden hose - if the roof (hood) is out of alignment, you'll soon know and they can tweak it. Once sorted, these cars are almost bullet proof but being hand built, the first owner may have to do some minor fettling. Low mileage cars are great but it often means that may not have been done.
Lastly, I've owned an e46 M3, e60 M5 and an X6M and despite sharing a great BMW engine, the Aero 8 is nothing like a BMW. It is simply too much fun to be even close and far less clinical. Bags of soul, personality and a sense of occasion whenever you drive it, is the way I'd describe the Aero.
Lastly, get ready to feel like a celebrity. You cannot drive these cars without people paying attention. As was said on this site, by an Areo owner, 'the car is the celebrity, I'm just the chauffeur!'
They aren't cars for those who want to go under he radar
Let us know how you get on
and i was all excited about having a good drive in her today.