I've been searching for a while and can't find any details on this.

I'm planning my future install in my new 8 and I need some details on the stock bose system. Mainly, I need to know how far back the flat source signal goes before being processed by the bose system. Let me give you my system plans just in case it matters.

I'm planning a pseudo-DIY 3-way component system for the front. The doors will house Dayton 7" midbass drivers (rs180's) and I plan to deaden the piss out of them to kill rattles. The mid/tweet combo will likely be either Oz Audio Matrix Elite 5.25 components or Critical Mass 5.25 components.
I plan on incorporating some kind of time alignment processor into the source line, but I haven't found one yet. In my Grand Prix it was done by the deck, but that isn't a likely option in the 8. A Kicker kq30 will be used for fine tuning (30band eq)
I haven't decided if I'll be going totally active with the fronts, but I have that option available.
The sub will likely be an IDQ 12 or 15 (based on space) in an IB configuration.

So....all that said...you can see why I'd like to keep my LOC in the trunk if at all possible. Is a flat signal sent to the bose amp in the rear or is it processed somewhere up-stream?

I'm open to any suggestions from the veterans as well. I'm not new to the stereo game, but I am new to using a stock deck with high end components.

The Bose EQing is added to the signal inside the Bose amp in the trunk.

You should take a moment to read the audio install sticky.

On the underside of the rear deck you will find the Bose amp. Going into the amp there are two plugs. The Blue plug contains all the signals that are unprocessed by the amp. The beige plug contains all Bose processed signals.

In general most people with a powered LOC tap into the signal before the amp. If you have a passive non-powered LOC most people tap after the amp. Also FYI if you are using High Level inputs most people tap after the Bose Amp.

If you want to tap the rear inputs before the Bose amp find the wires on the blue plug:
LR+ is Green/Orange
LR- is Blue/Orange
RR+ is Brown/Red
RR- is Grey/Red

If you want to tap the rear inputs after the Bose amp find the wires at the rear speakers:
LR- is Pink
LR+ is Violet
RR- is Black/Blue
RR+ is White/Blue

I must have missed the car audio sticky, or missed the info in it...

Thanks for the help guys. I'll be using a powered LOC to get the output voltage I need. I haven't gone LOC shopping, but I'm not going to cheap out on that critical piece. It doesn't matter what happens after the LOC if sends a shitty signal.

Also, thanks for the color break down. That'll help down the road.

Use the Audio Control 6XS and tap the signal before the Bose amp. There should be more info on it in the sticky.

My amp has all signals (in & out) w/ the exception of the center channel, on one plug.

I also recommend going ahead and using all 4 channels to keep your factory fade.

Well seeing as how you're keeping the factory radio..... wouldn't it be only obvious you would tap on the headunit output/amp inputs?

yes, that would be obvious. What is not obvious is if bose placed an outside eq or sorts somewhere downstream from the deck and upstream from the amp...hence my original question that was quickly answered above.