You can try using it without a coupler or amplifier. My house is over 2400' and I never had any problems. I did install a amplified coupler after a few months just to be sure I would never have problems.

Installation of switches is very easy. 3-way is a little harder, but not much.

4040 is Smarthomes part number. Like Daniel says, they never use the correct part numbers... they make up there own.

Chris