That looks like exactly what I want to do. I am looking at the GIVI E55 Maxima 3.
I have a 2008 with stock seat and I would like to have the ability to buy an aftermarket seat with a bottom back rest for my wife.
Which Premier rack did you use?
Did you have to make any modifications to the rack?
Which Givi Box are you using?
The top backrest, is that Givi, Premier, or Other?
Do you have the Givi brake light and if so did you have to make any modifications (Premier's website says you do need to make modifications.)
How does it feel?
It looks like you can fully open the top without getting in the way of the back rest.
Anything else you can offer is appreciated. Thank you.