I got my Shad 50 last year. The mounting plate mounted on top of the stock flimsy rack. As stated before, it came with new longer bolts. It made the stock flimsy rack less flimsy.
The trunk slides right on to it. If you lift the trunk handle up, you can slide the trunk off and carry with you are just ride with out it.
Without the trunk on it, the rear rack with mount doesn't look ugly.
While driving, the trunk will wiggle ever so slightly from flex in the rack, more like a vibration. I have traveled 3000 miles with the thing loaded up, no problems.