Ok, I'm confused. Where can I go to read about this? I was under the impression that changing a tx crystal was ok so long as you were within a certain range (speaking specifically for Futaba which has upper and lower).
You can search the radio forum for more info but To read about it go to the FCC website it is a FCC regulation on the band we share with other users. Our freqs are considered secondary and cannot interfere with the Primary (i.e. paying) users.
What you can do is change the crystal in your rx to find more about this for futaba look at there web site