Hey Zeke,

I do the same thing for my Nav and phone but I do not use the Aux input. Instead, get either a ground loop isolator (for line level inputs) or a Impedance matching unit (for speaker level) and connect them in parallel to the outputs from the empeg into your amp. You then do not need to worry about switching and the associated clicks. This works perfectly for me and I cannot hear any crosstalk from the empeg at all. The other benefit is that I have my empeg to mute to 50% from either the Nav or the phone kit mute line and the relevant sound just overpowers the music but without it stopping altogether.