RF stands for the interface or head unit, if you can call it that, that went right under the dash. To the left of the steering column, to be exact.
If you are just going to do rear speakers, make sure you enclose them. Most audio shops have 6x9 'shells' that will cover this. Also, as I mentioned, the Hidden Audio components are not the best. I think someone had mentioned they were lower end Pioneer audio components that had been OEM'd. With the newer systems today, you can get the same type of set and remote with an Alpine, Kenwood, etc.
Hey UT,
Depending on the weather, I would take a heater pointed at my crotch versus some tunes.....
- Paul