I've had the same tube for a couple years, so I forgot what I paid. $5.95 sounds great. A little bit goes a long ways, the end of the tube has a little sponge applicator. Just apply it sparingly. A couple hours later I wipe off any excess, but the directions don't say anything about doing that.
I've never seen any streaking. I also use it in the rubber tracks of my slow moving windows so they glide like new again. (Once a stealership said I needed a new window motor, then I read in Roundell about BMW's Gummi, it worked!) I don't know if the BMW brand is the same as you cited. Does gummi-flege mean rubber care in the german? The tube says it also helps to keep the seals from freezing in the winter (we don't get that cold here in the winter, so I can't say anything about that).