I'm looking to purchase an S550 4Matic. Various online "sale" sites has yielded prospects, ranging from 2007 to 2011.
It would be nice to find one with under 100,000 miles but in a couple cases, I've found an older with 80,000 mi vs a newer with 125,000 mi.
With cosmetics and everything other things equal (no bad stuff), my inclination favors lower miles over new year.
My research found potential future repair expenses for an S550. Motor mounts seem to be prevalent and very expensive.
Other "gotchas" include air struts, blower motor and general suspension items
Finding a seller with good maintenance history is like looking for a needle in the haystack,
Lookin at CARFAX, I'm hoping to see an entry by a MB dealer, "Motor mounts replace at XXX, miles" Or, "struts replaced at XXX miles".
Prior to purchase, I plan to have a PI done by either a dealer or a good independent shop.

My process is complicated because the potentials I've found are 3 to 6 hrs driving distance from me.
An approach (that I scratched off my list) was to call a dealer, pay for a PPI and have the seller take it in. Then the dealer sent me a summary of good/bad, ugly
I don't mind paying $200 or so, but with my current prospect list of 5 or 6 cars, it would be nice to narrow it down first
My instructions for the PPI are not just to check out the components but to eyeball components to see if they are factory original or replacements
Unfortunately, my screening and checking out process doesn't happen overnight and like the good women and good cars are gone before i can make my move.

This leaves me with a few questions:
* Are any of the model years I mentioned more or less prone to motor mount failure?
* Is there a "sweet" year?

On a logistical issue / transportation issue to my home in Michigan,
If I buy in-state, my insurance agent will add coverage immediately. With a signed title taped in back window, it's legal to drive home.
Most of my possible purchases are in Ohio, Indiana, Illinois and I don't know what is legal.

Last question: Is there an owner of a unicorn on this forum located close to me that has the perfect car for me, with detailed history and wants to sell?

 

Motor mounts will fail on all models at some point. My Sl550 2007 (R230) with m273 engine failed at 30k miles and 2012 Sclass with m278 engine at 90k miles. The model years you site have m273 engine. Get the transmission mount replaced at the same time.
Make sure the car you buy has a service records that conforms to MB maintenance schedule, and if serviced properly the higher mileage cars can be very reliable and more reasonable.

 

I know the mounts will fail sooner or later. Aside from finding a car where the owner had the mounts were replaced yesterday, (and documented) are you saying a car with lower mileage is preferable to a later modle year of vice versa?

Example: 2008 with 80K miles vs 2011 with 150K miles.