Last year, I replaced my prop shaft, stuffing box hose, and stuffing box. Here's
one place where you could source the materials. Gotomarine is another place you could check.
(The link I gave you is for the size of my boat, but you can go from there to find the size for your much larger E38.)
If I had to guess, the stuffing box hose on my boat was factory original. Although it did not leak, I did not trust it, not only due to its age but also because Ericson ought never to have installed such a hose in the first place. (The boat builders of these production boats often cut corners and Ericson was no exception.) Proper stuffing box hose is MUCH thicker than what I took out, as you'll see from the pictures on the site I linked. Yes, it did hold up for many, many years; for that I'm thankful. But granting that it is mission critical and can sink your boat should it fail, it's best to use the correct stuff.
My original stuffing box was actually just fine and I could have continued to use it. But granting the overall costs involved in swapping out the hose and prop shaft (which did have too much wear at the stuffing box junction), I figured I'd put in a new box while I was at it.