The difference in fm modulators is if you get the wired or wireless ones. ones that just plug into your cig lighter are crap, and don't have enough power to make it over anybody elses modulator. the only way to do a fm modulator is to get a powered in line one. ones that connect through your antenna but also have to have a power supply. then you will most likely not get any interference, most likely. I have also read about an aftermarket addin to add a aux input into your deck but read that some people have problems where you have to have a cd playing in the unit for the aux to work which just seems odd to me.
