Just some info for anyone else who wanted to know the difference:
Line Out actually lines out the output signal going to the speakers, then sends it out. That way, if a sound plays in the back-left speaker (for example), then the sound will only play there. RF Mode plays the sound in all speakers but plays it louder in the specified one (the back-left in this example). That makes RF Mode better for noisy areas in the day time, and Line Out better for quiter places at night.
Just thought I'd let everyone know.
-Closed-