So thats quite a few questions in one hit.
WAF for our first Series 2 was so good she kindly put her own hand in her pocket and paid 25% of it.
Things to consider.
Getting in and out remains a slightly non-feminine occupation as the doors are shorter etc. Might be worth a test if the lady like skirts.
I would expect there will be a few niggles worth fixing on the roof water tightness but the platform is pretty solid and the development through most models seems to be good now. I will leave to the S5 owners to report on water ingress.
If something does go wrong it tends to go away for more than a day whilst the problem is sorted. Parts are more unusual so not always stocked. Who is your local Aero skilled dealer?
Get a sump guard fitted as the 4.8 is a little exposed.
Sounds a little bit negative but given we have the S2 and a Coupe you can see I love them despite the occasional frustrations. It is not as reliable as the MB and I would not advise most people without access to another car to think they can get away with this. As it happens we still have an MB as a sensible car. I think the more you use them the more reliable they remain.
Despite all that I would say if you can then do it. As you say the car rides and drives surprisingly well. The sidepipes make every journey a hoot.
Shooter has had a series of Aeros he has put high mileage on and experience of an S5.
I don't think we will ever be without one now.
