So the throttle switch failed on, on the 900Mhz vehicle.  The 400Mhz vehicle which was modified had no further problems.  The stronger pullup resistor & lamination of the switch would have to be done to the 900Mhz vehicle.

The next problem was the steering buttons.  These have to be replaced every year.  They got some life extension through  wrapping in packing tape.  The last wear comes from sweat which manages to get around the packing tape, holes in the packing tape, & the amount of abuse.  They's constantly banged for minor steering adjustments.  Eventually, getting good contact requires pressing the buttons sideways.  Later on, they lose their springiness.  

Attempts to make the steering buttons more tactile involved making the center buttons closer together.  This provided clues as to what buttons were in the center., but it meant they couldn't be pressed sideways.  A new idea is to space all the buttons enough to press them sideways, while grinding the buttons at different angles to indicate which button they are.