In regards to limited range, probably weak battery in the remote. Secondary possibility is that something is wrong with one or more of the antennas in the car. If I recall correctly, there are at least 3 antennas. (L door, R door, Console) If you have a Tech II (or other soon to appear products), you will be able to see if the antennas are operating properly.
In regards to radio settings, I believe you could have different personalization options for the remotes. Perhaps for one FOB, you don't change radio settings, but the other one does?