The 5945's are almost as fast as the 5625's if both are ran on 6 volts. The Yak is a great flying plane but I chose not to use the higher priced servos in it due to its size. I saved them for the bigger stuff. As to speed, dntmn is right, the 5925's are wicked fast, I have them all around on my Wild Hare 260, except for the rudder. Wouldn't trade 'em. I like the response you get with the faster servo. In the Yak, you don't need 180 oz. on the surfaces & like he said, you can always change the gears if you put 'em in a bigger plane. I plan on flying planes until they are worn out so I buy for the plane at hand, not for the one I might get one day but I certainly understand the philosophy.

The rudder servo on the Yak does need to be pretty stout. Dang rudder is as big as a 30% plane. Using a weak servo here will show up in performance. In my 260 I have two Jr 8611's on the rudder. Figured there was no way a 33% plane needed that much power so I unhooked one of 'em. After one day of flying I hooked it back up. It was very noticable. I think the Yak could literally fly on its rudder it is so big so that servo needs to support the plane. 120 oz. on everything else will be fine, just maked sure they have a good gear train, no nylon or "Karbonite".