Subframe is completely rotted. Was looked at several times by different mechanics because the handling was significantly impaired, but was not found until it was taken for an alignment because it began shredding brand new tires at $150 a pop. Will be calling dealership ASAP, but do not have the extended warranty so seriously concerned this will be a HUGE expense and a run around. A common problem it seems. Absolutely unacceptable for a Mercedes. This SUV is gently used and cared for. This is a dangerous and hidden defect and we were never notified by Mercedes that this could be an issue and to be aware of it.