Mitko, welcome to this forum.
You will find a lot of similarities between the 850 Le Mans and the K100.
By experience (I was a Guzzi dealer in the 70's and owned an 1000 Le mans) you won't be disappointed by the K100.
The Le Mans had the integral breaking system (60% on the back and 30% on the front) and the latest K100 has ABS.
The fairing protection on both bike is about the same but the K100 is a lot hotter.
The Le Mans has about the same performances but not as much torque than the K100.
Finally, you get less high pitch vibration on the Le Mans.
Now, you know what to expect from a K100...... same enjoyment of ride.
Cheers
Bert