For the best engine offer available all year around, take a look here:
http://www.himodel.com/sort.php?sub2=CH
The ASP/Magnum .91 is 110$ but the SK 90 is only 66$[X(]
You could also use the SK 130 at only 87$
Doesn`t get any cheaper than this.
I have the SK .50 myself and it runs fine and have about normal power for it`s size. The SK .90 has been reported to be very good too, by someone in here. Xjet I think??[sm=50_50.gif]
I think you`ll want a .90 twostroke to be the minimum in this plane to be satisfied. A quick google rewiles that many use 120 fourstrokes on this plane.