I have the Saito 125 and it has been in an amazing choice. Vertical is all day long and no tuning issues at all. My friend when with a YS 120 and the pesky tuning issues of that engine caused so many dead sticks that he eventually stopped flying the plane. Well, he sent it back to YS to tune it, got it back in the plane and flew it twice with both ending quickly with dead sticks. On the second dead stick he lost the plane. The Saito 125 performance is a great choice for this plane and very reliable.