My Mrs. had a remote start installed on my truck as a Christmas gift. Mine had the exta fob that I had to carry around.....range was terrible. I ordered a key from the dealership with the remote integrated.....MUCH better range.

While I was at the dealership picking up the new key, the service manager said there had been a few folks asking how they could increase the range of their remote start system(s).... he went on to tell me the separate fob has the shortest range, and the key has the longest....but there is no way to increase the range of either beyond what it is. He also explained that range of either is limited as a "safety factor" by Ford.