I also debated about this and I really like the looks of the SH48. However, I decided to go with the sh50 because it is basically the same external size, has some color options and has a more robust relective strip around the case. I think that the SH50 space is more usable than the SH48 which is more angular. I also liked that the red from the case reflective strip ties into the red of the ST1300 taillights. I went with flat black (partly because dealing with scratches on the glossy part of my my sidebags is a pain), but can get a gloss black top if I want to later. I did not think I would need or want the SH50 pillion backrest with my Corbin backrest. (My wife loves the Corbin and wanted me to keep it.) However, I found that the SH50 backrest provides additional cushioning above the corbin backrest that my wife thinks will be even more comfortable.
I mounted the Shad on a PCA rack, that others here have recommended. By using it, I was able to mount the case just enough back to clear the Corbin backrest. The Corbin backrest tilts forward so that I can still open the topcase all the way. I did discover however, that I needed to drill holes in the PCA rack to make the Shad universal mount fit. I found this fact last night on a BMW forum. No one had mentioned it here.
One point to note is that, once mounted, the PCA rack extends a little beyond the back of the Shad universal mount. So, I am pretty sure that will rule out using the Shad light kit.
This is my first day out with this setup. I was using Dowco Iron Rider soft luggage before and I have noticed no difference at all in handling--even behind log trucks in the rain at 70 MPH. Also, this does not move around or make any noise at speed as some have said is the case with Givi.
I have attached a few rainy-day-in-Oregon pictures from my first day out. I hope this helps.
Mike in Southern Oregon
