I also have a funtana . I know the manufactor calls for a 100 size engine but it will be under powered. so the first choice was a saito 120 and it flew well. the balance was perfect and all manuvers were crisp ,but i needed a lil more power on pull ups from a hover im running a 18x4 wide prop and the 4 stroke has the ability to spool up faster than the 160 2 stroke most if not all 3d type planes will perform better with a 4stroke than a 2 cycle .you need prop wash not speed over the control surface the OS 160 is a great moter but not the best choice for the funtana to do the type of flying that your doing , play with differant props and run 30% fuel you will see a differance , have fun