So it's finally time to install my old gear in the G35. I've got a 2005 6MT Coupe with the Bose HU, no Nav. The gear I'm installing is going in because I've already got it all, it's the same system that was removed from my old 4Runner and money's tight so no reason to go replacing stuff that already works well.

The gear list:
Source: Pioneer DEX-P9 (with DEQ-P9 hideaway EQ)
Front Components: Focal Utopia 6.5 Component set (6.5" in the door, Tweeter either in A-pillar, stock upper door location, or modified kick panel, undecided yet)
Subs: 2x 12" Illusion Audio carbon Nd-12s
Front Amp: Xtant 4180x
Sub Amp: Old old old PPI Art Series 2350DM
No rear fill, never use it if I can set a good front stage.

I already mentioned that money was tight right? My initial plan (which still stands) was to use the Pioneer HU as a temporary fix because I can't afford a more modern unit (like the Eclipse AVN726e, for instance) and at the moment I also can't afford the $300+ for the double din plate with AC controls. My plan is to install the Pioneer in the upper pocket where the Nav would normally be located. I know that will have it's own difficulties but am not worried about that, my problem comes a bit later on...

As I was driving around this morning I realized how much I was going to miss having the 6 disc in dash changer. I also remembered seeing all the posts about adding a sub to a factory Bose system with a line out conversion on the rear speakers. I can plug an RCA input into the Pioneer and use an AUX source (and have in the past with XM and iPods) so I started to wonder, what would keep me from using the factory unit as a slave source to keep it looking relatively stock while (when necessary) using the Pioneer for higher quality single CD playback (and easier iPod integration)? An RCA conversion going to a sub amp vs going to another receiver is the same signal, why not?

I can't get around having to keep the Bose HU in the car, at least until after the holidays, and since it's there I'd love to get some functionality from it (plus even if I had the right plate to remove it and keep my AC controls, a single din unit in that space just doesn't look right to me). Any reason that couldn't work? I know of course that volume adjustments will be tricky with dual sources like this and I'm fine with that. Has this been done, or can anyone think of a reason it wouldn't work?

I know that there have been problems with converting the rear signal (due to low voltage levels) but it's been done. So anyone who's done so, did you run into any difficulties that might screw this plan up?

And yes, this is a strange plan I know. It's what I've got to work with and honestly I prefer keeping things low-key. If you look in and only see the stock unit you'll have less desire to break in to the vehicle.