I know lots of people have replaced radars w/mini-gps rcvrs these days. It works, I know. We've done it also. However, be aware there are times when you have no or poor gps signal. If you're operating in/around buildings or behind a row of trees. One has to consider if that's a hinderance for you.

I realize some radars have problems also, like dust or waving crops causing false signals. Wet roads also cause false readings, but that's generally not a big problem.