I tried these as an experiment in my 1997 E420... it did firm up the upshifts nicely, but the downshifts were too firm for my taste. These solenoids are used, they were in the car for about 2000 miles only. They are Y3/6y1 and Y3/6y2, regulating shift pressure and modulating pressures in the transmission.
Please do your research and make sure you want them! There are multiple threads on various forums discussing this upgrade. P/N 240-270-00-89, current MSRP at the dealer is $236 each / $472 pair.
Asking $375 for the pair, free delivery in USA, PayPal ok.