Its the same chap who did the two and three speed modifications and the full set of lights on a celica, so I think he knows what he is talking about
Running the above link through the translator you can see he is suggesting two modifications to the 4-band transmitter to improve it. The first seems to be replacing the antenna with the ‘old’ type. Not quite sure what he is going on about, anyone figure it out?
The second involves modifying the buttons. Must admit the buttons on mine are hard to push down, I’m tempted to try this one.