Actually, that's not "how that works". There's a lot more to 2-stroke power than just compression. Port timing and shape is of huge importance. An early 066 cylinder will be way better than what you slapped on there. If aftermarket parts were easy power boosts, everyone would be doing it, don't you think?
And beyond that, there's a lot more to making a good saw than power. Like longevity and reliability. Plenty of those aftermarket kits are out of round, out of square, have bad plating, bad port beveling, etc. They won't run for hundreds of hours like an oem will.
Edited to add: you still didn't tell us why the original top end was fried? Air leak? Ate something? Was the saw diagnosed before putting a bunch of aftermarket parts on it and calling it "built"?