I would have to agree also with the 4-stroke on the 4*60. I have a kitted 4*60 with a YS .91FZ up front. This motor has the power of a 1.20 and this plane is a blast with this setup. Hovering and pulling out with plenty of power in reserve. I am spinning a APC 15x6 at 10,000 rpm. I need to put a 15x8 or 16x4 to get the RPM down some to around 9000 rpm. I modified the rudder and elevator by adding 1" extra to both, so the plane now can Knife edge better, hover, waterfalls, hammerhead, flat spin, etc... I added a front hatch for easy access and battery placement for proper CG, pull-pull system. Each elevator half has it's own servo and placed a 14 oz fuel tank plus some extra mods I can't remember right now. I firmly believe this plane flys better with the extra power as long as the plane was well built if it is a kit. An ARF may not handle the extra stress as well. I flew a 4*60 with a Saito 61 which was too sluggish for me. The YS .91FZ has vertical unlimited power for a 8 Lbs bird.

Here is my 4*60 from another post on RCU with PHOTOS
http://www.rcuniverse.com/forum/fb.a...538&tostyle=tm

DTB