I'm currently driving a 2020 BMW 440ix Coupe and need to go back to a 4-door sedan. I have previously driven A6's and E-series. I have an opportunity to buy a 2015 S550 with 25k miles, Palladian Silver with Black Nappa, locally here in Denver for $49k. I don't have the build sheet so I don't know how this compares to MSRP, but I'm wondering if this seems like a good deal? It is a 1-owner driven 3,500 miles/year on average. It appears pristine. Any thoughts or comments or issues to look out for?
Many thanks in advance for any responses.

2015 S550 in Denver