I can only say that I have put de Q's upgrade into 3 e9's, both of mine and a friends; they make the up-pull smoother and due to the construction I believe the associated stock mounts will last much longer. If you are not replacing the cables you can lower the e-brake, remove the rubber cover, apply a small amount of grease, remove the retaining clip from one side of the original pin and slide the de Q Sport model into place in a matter of minutes by tapping in as you're tapping the old one out, once one side is in, remove the old pin and slide the "other half" of the new one in and tighten to taste.
On the other hand, if you remove the parking brake handle and lose the alignment you may have some very sore thumbs by the time you are done.
I don't know how many of these were produced but I think this upgrade should be as common as using synthetic oil and just as easy (maybe easier) to install.
Good stuff!