The sending units are not hard to program but read through the manual and thoroughly understand how to do it before attempting it. The setup process has to be followed to the letter in order for everything to work properly. It's easier to think through the process without attempting it as you're learning it.
The installation process is one of those things that could be as easy as 123 or get complicated. We had to replace the valve stems on all 6 wheels to get the sending units in a position where they could be easily installed and have sufficient clearance to fit through the holes in the wheel simulators (hub caps). In our case it added another few dollars to the cost, but since we were already planning to rebalance the front tires and replace the rears it wasn't excessive.
If you have to replace all the valve stems and rebalance all the tires expect to add another $250.00 to the cost.