Had a touring screen fitted to mine when I bought it. It was hideously noisy even when I chopped 2" off it.
Fitted a cheap chinese d/b a year ago and its been brilliant. Good wind protection, very quiet, and looks good too.
I've chopped that screen down to Just above the fairing, and it's even quieter with the clean air hitting my lid.
As slimwilly said, keep it short.