I also have an '85 190E. I changed my stocks with Bilstein Sports. I had to use a wrench, while using a Hex to hold down the screw( top screw) to unscrew it. It may be tough the first couple of tugs, but be patient and it'll come loose.
It's probably a good idea to change the rubber bump stops, the dust cover and the strut mounts, since you're taking everything out. Also, make sure to get some new encapsulated bolts for your new struts. Discard the old ones. Fastlane has most of the parts, except for the rubber bump stop, I think. Do a research on this topic, and you'll find many who recommend going with Bilsteins rather than Boge.
Hope this helps.