[jwight]

The single wrench is a service notification. You should also see a number with a minus sign before the wrench goes off that's the number of days overdue service.
The whirring noise is the secondary air pump - normal.

 

[jwight]

Badge engineering at its finest. There was no Brabus engine for US 451s.
PS - here's a source for the Brabus engine "badge" - Aluminium Powered by Brabus Badge Emblem Decal interior rear boot