You can send the radio and crystal to a shop and they can install it for you. You want to do this for more than just the "legal" reason. When a crystal is changed the radio must be retuned to optimize the output for the crystal. If not you can seriously reduce the range of the radio and jeapordize your plane. RCU member CGRetired recently purchased a radio that the original owner had changed the crystals on without having it retuned. When he sent it to the shop they told him that the output power was half of what it was supposed to be.

Yes, it is the law to do this. But aside from that, is crashing your plane worth the risk??

Ken