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I'd like to add my two cents worth on this subject...
I took the course about a year ago and completely agree with Nick's review. We are taught a lot of irrational things during our training. Often there's no data (only old wives tales) to justify the action. This course skewers a few sacred cows - and backs it up with data.
One point worth noting is that the course is not meant to convince you to run LOP, but rather it will show you that the window in which the POH tells you to run the engine is the worst abuse you can give it. The lesson is: either run it richer than 125 ROP or LOP, but not between LOP and 125 ROP (for greater than 65% power settings).
How do they justify this heresy? Simple. They demonstrate the CHT's, valve temps, and peak internal combustion pressures (aka theta PP) *all peak* in that "recommended" zone. If you want to be gentle to that engine, you'll operate it either richer or leaner.
It's widely believed that you will burn valves by operating LOP. They demonstrate that the valve and CHT temperatures are lower LOP vs. the "POH way." They also show actual burned valves to you and explain how they ot that way (hint: it’s not because of anything the pilot is doing).
And just to show how entrenched this "you'll burn you valves" thinking is, then pose the simple question: Which is hotter, 50 dROP or 50 dLOP? Most will answer: 50 dLOP is hotter because it's burned into everyone's head that LOP is hotter. By definition, both of these temperatures are 50 degrees cooler than peak, and therefore *must* be the exact same temperature. But we don't let go of our old wives tales easily.
When you see that the valves and the CHT are cooler at 50 dLOP, and the theda PP is lower, you have to start asking yourself: How is that worse for my engine?
One very important thing I took away from this course was that the POH cruise climb fuel flows are not rich enough. I now do my cruise climb at full rich (roughly 20 GPH on each engine, '77 P337) and can clearly see the engine is much happier ("cooler") this way.
Don't assume this class is only for those looking to run LOP. If you want to run ROP, you will still learn a vast amount of information. For example, you'll see how to interpret engine monitor readings to diagnose pre-ignition, detonation, and even worn valve guides. This course is a gold mine.
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