One of the complaints I heard of Schnitz is they are not great returning emails.. While this may or may not be true, they were very responsive via phone and the turn around on the unit was super quick.
I have emailed him three times and he has always returned my emails with-in 24 hours or less. (he does not know me, I do not know him)
You mentioned that you were experiencing some engine vibes;
I noticed I had/have some also between 3500 and 6K, I wanted to re-torque the engine mounts but i just had the fairings off last week and did not want to pull them again so I just checked the rear bolts.
They were really off, One was hand tight at most and the other was in excess of 50 Lbs (should be 11lbs). So I tightened them to the correct torque and rode the bike. About half of what I felt is gone so the next time I have the fairings off I will do it correctly as per the manual... just a thought you may want to check yours.