Moped Army

Anyone who is doing 70 is not using off the shelf parts, or even close to it. Otherwise everyone would be doing 70. And your right, loop scavenging is a proven technique. In fact it's how the cylinder was already working. They are all loop scavenged 2 strokes. All of them. There are not that many types of scavenging in 2-stroke design and loop is by far the most used.

And your right, that is why those other kits have those ports in them. They are called boost ports and they help the air flow in the loop shape though the cylinder. The second set of ports behind the main ports are called 5th ports and also achieve the same thing. Getting more air though the engine and helping scavenging efficiency. Drilling holes behind the rings have been done for years too. Drag bikes used to use it. Similar idea to using a dykes ring piston, use the available pressure to force the rings against the walls to form a tighter seal.

My point is not that it does not have some effect but that it does not have the effect that I think is being sold here. IE snake oil. Learn this one simple technique discovered by a random dude that TRIPLES your HP!