NOTE: This is my experience with lifting a 2013 W212 E350 "Sport Model" with non-standard lifting accessories on a Quickjack 5000-SLX with QJ factory extensions. It may be safe, it may not be; this is supplied as information only.

So, I bought a 5000-SLX for my W107, several years ago and it worked well. I bought the pinch weld adapters and I had to widen them a bit to accommodate the W107 pinch welds. A concern with the W107 is the notoriously rusty rockers; they must be examined internally for structural rust, thoroughly, before lifting this way.

I realized that my purchase would not work well with the W212 that I bought years later. I had to buy the (expensive, "tall", and heavy) extensions. I know that some of this board have "barely" made the original length models work on the W212 but I don't see how this could possibly be done safely. I took a look under my car and I noticed that one of my plastic inserts for lifts had been damaged a bit by a previous technician's lift; I bought a new Febi replacement. These aren't very expensive and fairly easy to replace. I bought "hard rubber" "puck and bar" inserts on eBay, These are urethane, and simply too soft to use IMO. I wanted to buy the "good" aluminum ones from Reverse Logic, but they are always out of stock. So I bought the common aluminum items, shaped like the urethane pucks but the round part is shorter. These are smaller than the Reverse Logic units and don't have the spring loaded pins to hold the pieces up in the plastic adapters.

My 2013 Sport model E350 is VERY low to the ground, and adding the height of the extensions would certainly prevent the QuickJack from lifting. So I made four platforms from 3/4 plywood (two layers, stepped) to drive the car up on, buying me back 1.5 inches. I made them during the "lumber crisis" and I paid through the nose. The two pieces of plywood that they were made from were glued and screwed together. Driving up on them was no problem (the 4Matic might have helped here, could be tougher on 2WD)

I used "short" extension rubber blocks from QuickJack with the aluminum puck for lifting. It was tricky and slow to get everything aligned. I did this outside as I discovered that the W212 is quite a bit larger than the W107 in my garage! I had determined that my driveway has a two degree slope, which is the safe limit as stated in the QJ manual. (Tip: An iPhone has an amazingly good level built-in.) I would absolutely not exceed this slope.

Once aligned, I lifted the car without a problem. Not having the superior Reverse Logic pucks that can "stick" into the plastic adapters on the car and then you can align the blocks to the pucks made this much more difficult that it should have been. The cheaper aluminum pucks from Ebay, Amazon, etc. are also smaller, and may put a worrisome strain in terms of pounds per square inch on the plastic inserts on the car. They had to be smaller, or aligning them would be even more difficult, if even possible at all!

The rubber blocks from QuickJack deformed more than I would have liked them to. Maybe the deformation prevents them from slipping off.