My AMG cars. 2005 SL55 and 2008 CLK63 Black Series neither have ever been in the rain. The SL has 10000 miles on it and the Black Series has 1700 miles on it.
We have had all the SLK AMG Models over the years starting with a new SLK32 bought in 2001. After selling my C8 Corvette, I wanted another SLK32 and found a pristine 2001 with 39K miles, then modified it. It has 19" wheels, PS4's, Sony AX4000 NAV/AppleCar Play, Backup CAM, new Homelink Mirror, Windscreen, refinished interior, new ignition, K-40, Bosch 010, Needswings larger pully and intake, V-Tech Tune, Bilstein Coil Overs, MSS 2nd Key and TCU. More recently added a similar already modded (Sony AX4000 with CAM) 2006 SLK55 with 62K miles and a Kleemann Supercharger, est. 520HP. That has a supersprint exhaust, extensive updates and upgrades.