I have heard of more oil makes more power. But I think this applies only to some premix oils which have a small percentage of nitro in them which causes the power increase, but I can't remember specifics. I also posted an explanation on another thread that using petroleum oils for break in seats rings faster, but synthetic oils reduce friction so much that rings take much longer to seat. This should indicate synthetic oils reduce engine wear and extend engine life after break in. However, with chrome/polished bores, better tolerances and improved metals this is not as important an issue as it used to be.

The real problem is that most oil producers will not give the consumer the technical information needed to make meaningful comparisons. Most people have no idea how much complexity and variation there is in oil formulation is these days. That's why you can mix some at 20:1 and others at 100:1. It is all blurred in some fancy marketing scheme. Fortunately, most of it is good enough for the average guy.

Break it in on the easy side, don't overheat it or overrev it, keep combustion clean, use good oils, don't crash it, and most engines will outlast you.