 I purchased a pre-owned SL600 in spring 2013, and problems occurred almost immediately after leaving the lot.  Dash displayed a TPMS issue, so I brought it back to find out that sensors for this were never installed but I could add them for $200 per tire.  Less than 3 mo/3,000 miles later a hydraulic suspension hose burst lowering the car to the ground, and replacement for this was nearly $3,000.  Even after repair the mechanics were not able to clear the suspension error in the system.Jump ahead another couple of months and I am roadside again, with a tire blowout due to an improperly mended cracked wheel. The Dealer was kind enough to cover replacement of this however.  The water pump also failed shortly thereafter.Over the next couple of years of ownership, I racked up quite a service history.  Brake assist system failure and replacement, more suspension parts, interior and exterior door handles, folding roof mechanism, wheel bearings, battery, differential replacement, several other issues, and regular but expensive maintenance.  Repairs and service exceeded 70% of the original purchase price (which was not cheap) and the warranty barely covered half of this.With a total of 35 days in the shop and 5 roadside breakdowns over 3 years I did get pretty familiar with the new models and the loaner program, which was nice.  But for the price I had to pay to keep this car drivable I could have hired a car service.  Operating cost was over $2.50/mile for less than 17,000 miles, not including gas, tires and other consumables.The car was a humiliating laughing stock at the office, and I actually feared driving it not only for my own safety but anticipating the next catastrophic repair.  When I returned the car it was explained to me that it still needed at least $5,000 of work, but I had enough.  The way I see it, either the dealer was aware of the many issues with this car and didn’t disclose them, or did not thoroughly inspect and sort them out before purchase (maybe both).  Neither explanation is acceptable. I will never again purchase a Mercedes-Benz product.