Sorry to write in english but my German lessons at school are too far

My R1200C Cruiser year 1997 gearbox is broken
New parts are too expansive and this model being quite scarce, very few 2nd hand are available
I have been informed that R1100S gearbox would be compatible with Cruiser
As it has the double advantage of being more available on 2nd hand market and could offer 6th gear, I'd like to explore this option
Therefore am looking any feedback from someone who has already done this swap and would like to know if it can be fit like Lego bricks or if it needs some adaptations
Thanks for your feedback
With best regards
David