"Let me start out by saying that like all cars and trucks there are good ones and bad ones. On this car I got a really good one. Thanks to CARFAX I was able to find out that this was a corporate car that changed hands every year but was also very well maintained. Like any 18 year old car is did have a couple flaws 1) low oil light in (easy fix just changed the sensor during oil change and no more problem) 2) front seats showed wear to leather ( also easy fix found a company online that makes original LEATHER replacement seats. $368 later new seats) and the only other thing that the car DID NOT NEED but I wanted since there were a couple of SMALL clear coat problems was to factory repaint to original. Costly but I use a good shop (Dealer cost $5500 my shop cost $3600 and that was stripped to bare metal and done just like Mercedes does at the factory)
The other thing and I would recommend to anyone considering this series of cars be it the S-430, S-500, or even the S-600 would to wait and look for one that has the AMG kit on it. The AMG kit is on my S-430 and includes special rocker panels, lighting both inside and out, better head lighting and rear lights, special seat options with extra memories.
The 1 and only downside to this car is the sound and navigation system. The sound system is great BUT you CAN NOT upgrade it to an off the shelf replacement because up to 2002 they used filament wiring and the only way is to rewire the entire sound system to hard wire. The navigation system is also dated because it uses 4 different U.S. disks and since 2005 they are NO LONGER made. And finally, the phone system is out of date. They used a Motorola phone in the car that no longer works in today's world, but again a simple fix just add a hands-free adapter. I chose to use a clip on JABA that is as good as my NEW 2019 truck.
Overall take your time looking and be sure to check the car history the early S models of Mercedes were susceptible to electrical and computer issues. If you have a good set of metric tools and are handy look on YOUTUBE 99.9% of the repairs and parts are there and explained. Enjoy your new top of the line Mercedes, I sure do "