Just curious if anyone has replaced one or both of the op amps that are in the Anytone for an upgrade or better audio while transmitting? It has two 4558s. I have heard that 4580s would be an upgrade but curious if anyone has tried any upgrades to the op amp in their own 6666. Hifi mods/capacitor change outs done. Just looking for a little more fun out of it. Before attempting it semi blindly.