I had a 46LA sitting around so that's what went in it. I spent so much extra time building and modifying my 4*40 that I just wanted to get the SE done and in the air. The next SE I build I will probably do all the same mods I did to my 4* and put in a bigger engine, or maybe I'll just do a 4*60 and put in my Satio 100 4S.