Very difficult to get these especially in excellent condition like this one with no scratches/marks whatsoever. I have just finished using this on my turbo setup and can guaratee it works perfectly.
I initially had trouble controlling boost using my ECU on a twin scroll twin external wastegate EFR setup and went through 3 different MAC valves before I resorted to this Blitz i-color DSBC and never looked back. It held a dead flat boost curve all the way through the rev range and I was able to configure boost by rev to give me more usable power.