I have the WiiHobby Yak 54 (1.40 size ).
I bought mine from Harris and Anderson R/C and Hobbies , e-bay name ( highresolution10 ) and my kit was perfect ( $169.00 + $30.00 shipping ).

Pros of the Yak.
Built nice and strong.
Covering was good.
Nice looking plane.
Flys great.
Good 3D.

Cons of Yak.
Control horns.
Very tail heavy.
Total overall weight.
Weak landing gear.

I put a Brillelli 36GT ( 36cc gasser ) in mine and still had to add nose weight.
I can't see this plane flying on the 1.08 that they recommend.
A 1.60FX would do it, but you still need nose weight and this adds you to the same total flying weight with what ever motor you use.
So I figured make as much nose weight as possible useful, anwser, gasser.
This plane has unlimited vertical, but is not over powered by any means.
A 40cc gasser is perfect for this plane.
I am changing the landing gear to a taller, swept forward gear.
I need the taller for a bigger prop and the swept forward for gear handling.
I can hardly even taxi with out nosing over.
The CG is set perfect, it is not nose heavy, and I can't keep it from nosing over.
The swept forward gear should fix this.
RTF dry weight is 14lbs 3oz.

Here is a link to see the Yak, mine is at the end.
( http://www.rcuniverse.com/forum/m_44..._1/key_/tm.htm )