Well there's a bit of a story behind this. I bought a Grubee Skyhawk 66/80cc a year ago, and it has bit the dust. At present, I have not been able to get it running again. So, I put in an order for 5 Grubee Skyhawk engines. Three for a friend, and two for me. I ordered with bikeberry.com, however they are currently having some serious backorder problems. After nearly two months of being in backorder, they offer me Flying Horse engines instead of the Grubee engines, for a partial refund. My understanding is that the Grubee engines are much higher quality, and for that reason I am inclined to just suck it up and wait a bit longer. So, my root question is, what kinds of experiences have you guys had with Flying Horse and Grubee engines? Do you think it would be worth the swap? I don't want to swap them and find 2 of 5 engines unusable or something. What is the level of quality difference between the two?