Hi Andrew,

That OS120AX is a great engine. A fellow at the local field has one and it really pulls...I have a Saito 180 in my Cermark Pitts and it has plenty of power, but the heavier engine/muffler assembly, along with the onboard glow driver and battery pack really add to the all-up weight. I also used some Engine vibration eliminators from Apache Aviation which add a little weight but work great.The model is pretty fast....I have not weighed it. I do think the 125 4-stroke would be too little power for aerobatics, probably fine for just crusing around and sport type flying...The OS120AX gets my vote...

Randy