RE: Changing out Hitec radio crystals
There are very valid reasons for having a qualified shop change transmitter crystals. The shop will tweak the oscillator circuit to put the transmitted signal exactly on frequency. They will check the shift frequency and adjust if necessary. They will tune the amplifier stages for maximum output.
While the FCC requirement may or may not eventually fall to the trend toward deregulation, having your crystal changed by a qualified shop will always be the best policy.