Garmin Integration Questions '05 Blazer

[CalixEros]

I bought my girlfriend a Nuvi 660 and will be putting it in for her within the next few days. I want the install to look clean and be hardwired. I want the power wiring to come from the RAP. Any idea where the best/closest location would be?

 

The biggest questions I have is regarding the GPS audio connection to the head unit. Ideally, whenever a signal is coming from the GPS (like when it's telling you that you have a turn coming up), I'd like it to interrupt whatever she's listening to. I don't think something like the PAC AAI-GM12 (or 24, not sure which one) will do that. Can anybody confirm? I hope there's something that will do this, but if not that's what I'll end up getting so she can also use it as an mp3 player (I know the 660 has a built-in FM modulator, but I'd like higher quality than that). If there are any less expensive alternatives, I would appreciate those as well.

 

Also, if anybody has a good suggestion on location for the unit (and maybe a mount), I'm all ears. Thanks in advance.

[CalixEros]

Basically I'm looking for whether or not the Garmon has a mute wire or if there's another way to create the same effect. I thought of something else. Say the Garmin is plugged into the adapter shown above, but she's listening to the radio and not the mp3 player. Will this keep the internal speaker from working and she won't be able to hear any Garmin directions until it's turned to auxiliary or it's unplugged?? Thanks.