saito 220.....gonna be hard on fuel ( to perform you will want 25% nitro i would say cool power 25% heli. 28.99$ a gallon 105$ per case; 4 gallons. ) but a 220 will be much better performance than a gas engine in this size. Gas engines don't perform well for 3d untill 50cc. They are great for flying scale, sport, or that kind of plane but for 3d performance they just dont have the power to weight ratio that you want for 3d. i would say either a 180 or 220 but if your gonna do it do it right and get the 220.

just my 2 cents. see what other people say to and take all options into consideration. i recently flew a funtana x 100 with a zenoah 20cc gas engine. it was an awesome plane but 3d performance would not be spectacular.