You are going to need to add weight to the nose of your Tiger anyway they are almost always tail heavy so the OS 55 is not going to add any weight to the plane...They are just a tiny bit heavier than the 46 anyway....The only reason I promote the OS46's is because I have had better luck with my 46 motors...They just run better for me although the OS55's run great too...John is probably rite , the OS 55 might be a better choice..Its a toss up really...But you will not save any weight with the OS 46....