I’m just gonna get all the bias out front, I was a general manager of two different brand franchise dealerships previously before making a career change in 2020.
I am not completely sure what additional warranty comes with either Lexus or Mercedes if you buy them certified preowned from a franchise store, but generally there is an extended warranty that comes along with that certification. In addition, to get that certification it has to be fully inspected by a manufacturer prescribed checklist at the franchise dealership service department. These are two huge value adds in my personal opinion, because both dealerships I worked for had used vehicle only stores that were separate companies and I saw how that side of the business works. If you buy from a stand-alone used store, the vehicle *most likely* has just been sent through a jiffy lube to have the oil changed and *hopefully* safety aspects (brakes, tires, etc) inspected. They also cannot certify the vehicle. This is to save money. At a franchise store, the used car is inspected by the franchise certified technicians and they charge a higher rate to the sales department than even a customer would pay the service department. Invariably, this is where you will see some differences in price that make the used store look like a better deal. One store I operated was a Nissan store, and a shop bill for a vehicle that needed to be certified and needed easy shit like new tires and brake pads was easily pushing $850 for my cost. A NISSAN. That has to be factored in because we aren’t trying to lose money, unless the piece gets super old on us and we need to free up the cash to buy better product. That’s why stand-alone used stores *often* will just do the bare ass minimum through a third party service station.