My factory racks and cases are in storage so can't comment on the width. I swapped the whole factory rack system out for givi side racks and an AdvMotostuff adjustable top rack for the Givi top case. The factory side racks bolt to the factory top rack, so you can run the factory top case by itself, but you have to have the top rack on to use the factory side racks. And the factory top rack will not accept a Givi case. I know that the factory top rack did not accept the AdvMotostuff Givi rack, but did not try it with Givi's rack.
Adversely, Givi side and top racks are independent of each other so you can have one or the other or both.
I don't know how big a deal this is to you, but I didn't like having a ton of keys with me, with the Givi's you are able to re-key the whole set to one key. Seems silly saying it out loud but that was a factor in my decision. Other than the fact they were color matched, I didn't like the looks of the factory cases either.