This manual lists airspeed and altitude as secondary functions. If you are experimental, you're not bound by certified requirements. You can legally...
If you install a new engine, you are required to log that information. Remember that some AD's may be based on date of manufacture or time since new...
If you turn off the power to the Tailbeacon you should get a normal transponder out signal. If ATC verifies that, you'll know that the transponder is...