Pleased with mine Jeff. 30mph right out of the box.
Improved to 38mph with only some careful sanding of the head.
Vibrations are not bad. Mostly Allen head fasteners.
Head studs are good, other studs fair (better than the other kit), replace all the nuts.
It was a plug and play. power is much better than my "No-Name" engine.
Air filter on all of these is poor if you ride in dust or dirt. Get a better air filter.
Stock carb was jetted close (slightly rich, lowered float to tune).
Far from a Honda or my beloved KTM, I am still pleased with it after a dozen tanks of gas.
Steve