And typically you will remove the headlight wipers. Then, unless you intend to spend big bucks for wipers that will work with your new lights, you will need to purchase new underlight fascia pieces and have them painted.
The old ones will have the ugly hole where the wiper shaft originally came through.

Also, if you intend to run anything higher the typical 55 /65 bulbs, then it would be smart to do the wiring using relays. All this is documented fairly heavily in the various lists.

Personally, I originally installed the Bosch units with the vacuum height adjustment on a '90 300E. When I traded that one for a '92 Sportline, I made them agree to let me swap out the lights. Did it right on their lot. Currently running 100/130 which is sometimes a little too much light. Think best might be 80/100.

Steve