the modulator usually operates on a couple of channels so you have a selection of like 3-4 channels there if there is a station you dont overlap it. Like the one i posted says it works on 2 channels 87.9 or 88.3.
The one i posted doesnt require splicing on the antenna but does require spling of 12V and ground, then acts like an inline sort of thing where your old antenna plugs into it and then it plugs into the radio antenna jack. Just have to make sure you have the proper antenna adapters (it mentions female/male motorola so make sure the dodge antenna to yours work out right).
The one i posted does have an on off switch included which you can bring out but might require some cutting to make integrate somewhere. If you leave it on it can distort local radio stations so its nice to have the on/off switch.
Overall I'd say look at the crutchfield page and the reviews and see what all its taken some people and what you get and what your getting yourself into. Its not that difficult but if you've never done any wiring before it'll be an adeventure
