I have few also. Communication with Frank is very good, he is always replying on emails which is a very big positive comparing to some others.
Surface quality is I would say 8/10 where 10 is Akrapovic carbon parts. Sometimes I needed to work a little with some edges to make it fit better, but overall I'm happy with my purchases. I did order few times from him for different bikes and he also did some custom works for me.
Buy one part, if you will be happy with quality, then order more.
Here is couple of photos of some parts:



