So I'm not going to pretend I know any more than the average guy when it comes to this stuff. I've owned a ton of bikes and modified the suspension on more than half of them and I'm still learning.
That being said this seems to be a very cost-effective and worth-while modification. I have not tired it with stock forks because I had my F4i forks with the Ohlins cartridges mounted but the rear end seemed to stay completely composed and less harsh over sharp edge bumps. The street ride I took last night seems to have confirmed that Steve was able to change the shim stack and match it to the oil weight very well.
When you consider the next best option is to buy and F3 (or I guess R6 now) shock, change the spring, mess with the length and possibly the internals, this mod it to me one of the best bang for the bucks I come across for the 919.
Please keep in mind I am not an expert. I seem to be in the minority in believing the stock shock is not best thrown in the trash. But damned if my bike isn't railing corners better than it ever has before.
I paid Steve $105 ($100 sounded better in the thread title, sorry) I am not affiliated to him in any way whatsoever, so contact him about pricing first.