Hi.
I got the same problem. I got two Vortex servos and to fit them in I needed to lower the radio tray by 4(!)mm for usage with the shock absorbers (3mm still w/o) which is very critical on the steering servo where 2mm on top and on bottom is the absolute limit and also just possible with cutting out the side guard.
Now I have two pricy Hitec servos and can't use them with the shock absorbers. And running servos with a "Glockenanker Motor" (
http://upload.wikimedia.org/wikipedia/c ... vorne.jpeg) w/o shock absorbers has some risk on the run. What a mess in "standard servo" industry with all the different heights from the lower edge of the mounting wings to the top edge of the servo output gear! That can't go on that way. And the best thing is ... try to find out the complete measures before you buy a servo! Impossible on most brands.