Ivan just completed a 1574NM flight and sent me this note:
"Just returned from my trip to Red Lake in NW'ern Ontario. The CPI performed perfectly, I did an in-flight EI check (aka a mag check) while running LOP and found a very small RPM drop and a bare perceptible note change in the engine when the LS was turned off.
Interestingly enough I found a very slight roughness in the engine when the CPI was turned off. However, in fairness I will have to say the the difference between the two EI's is very little.
As far as speed gain is concerned I may have gotten one or two kts. If I had changed from two mags then I might have seen a bigger gain but that was not what I was looking for nor did I expect it. The real gain here is, in my view, the reliability and a smooth running engine and I got both with the CPI.
So far I am very happy with this new addition to my RV-10."
Pretty good numbers. Note that Ivan is using one Lightspeed and one CPI.