I wrote a review on the Givi here,
https://modernvespa.com/forum/topic42806?highlight=givi#588991
It was "factory" installed at Bikeweek... I will admit, their install job was pretty ghetto. 6000 miles later, the case is still on, not shifted, but... from the looks of it from underneath, you would be surprised. The metal clips 'barely' cover the factory rear back cross bars.
I am almost noticing the snap/lock is starting to wear. I use mine... 4 times a day. I absolutely f*cking love the concept. I snap it on the scooter in the morning with my stuff for work inside, snap it off when i get to work, back on for the ride home, off when I get home. After 2-3 months of this, I need to practically sit on the top case to get it to lock back in. Doesn't want to snap back.
It does, but, you really have to put alot of pressure on it.
Love the case though. If this one wore out, I would buy another. It fits my 17" MacBook Pro inside a thing laptop bag perfectly. For my daily work commute on a scooter, this is great. Plenty of room for other items. One of the best buys I've made for my scooter, despite the stubborn snap.