Since no one has posted on this subject for a while, I thought I'd do so. I've been overhauling my 2011 Turbo with the base audio system. I've replaced the front component speakers, the rear door speakers, and the center speaker. I'm also adding a subwoofer in the trunk. I'll post more as I do more.
The 4 midbass speakers are pretty cheap. Thin pressed paper cones, non treated foam surrounds. The rears have a whizzer cone, fronts do not. They sound poor and won't last long without the surrounds rotting out. It's kind of shocking in a modern car. The front tweeters are fabric domes. Not sure what fabric, but they're definitely not silk. The center speaker is similar construction the the front midbass, just smaller.
There is a separate amplifier for the system, it's in the trunk behind the passenger side trunk panel. All speakers are powered from this amplifier. This should make it pretty easy to amplify all the speakers and use the factory wiring, if desired.
First off, the midbass is all 4 doors is 6.5 inch, and a bracket is required. The factory design is something special, and I mean that in nothing but a bad way. A single bolt at the top, and a slot at the bottom, and the bracket and speaker frame are all one molded piece. The opening is too wide to even drill new holes without an adapter. Scoshe makes one, part number SAGMHR634, it's listed for the Impala and HHR, but it works on the Regal and a number of other GM models as well, even though it's not listed. There's a total of about 2.5, maybe 3 inchs of depth available, as the bracket lifts the speaker off the door by about an inch. Most speakers should fit with no problem.
The center speaker is a standard 3.5 inch, no bracket required.
The front component speakers don't have a separate crossover, both the tweeter and midbass are fed the same full range signal, and the tweeter just has a filter on it. This makes it easy to replace the system though as you can just use the input for the midbass into a crossover for a component system as I did.
Radio 12V red/lt. green + radio, black 44 pin plug, pin 44
Radio Ground black - radio, black 44 pin plug, pin 38
Radio Ignition (low speed GMLAN)
Radio Illumination (low speed GMLAN)
Factory Amp Turn-on white + radio, black 44 pin plug, pin 43
Left Front Speaker: On vehicles with amplifier, the speaker wires are (+) dk. blue – brown & (-) dk. blue at the amplifier, black 16 pin plug, pins 10 and 2.
Right Front Speaker: On vehicles with amplifier, the speaker wires are (+) yellow – black & (-)yellow at the amplifier, black 16 pin plug, pins 11 and 3.
Left Rear Speaker: On vehicles with amplifier, the speaker wires are (+) green – black & (-) green at the amplifier, black 16 pin plug, pins 12 and 4.
Right Rear Speaker: On vehicles with amplifier, the speaker wires are (+) white – black & (-) dk. blue at the amplifier, black 16 pin plug, pins 13 and 5.
Center Channel: On vehicles with amplifier, the speaker wires are (+) yellow/white & (-) black/dk. blue at the amplifier, black 16 pin plug, pins 14 and 6.
Subwoofer: (+) black/brn & (-) black/grn [left channel]; (+) green/pur & blk/gry [right channel] | amplifier, black 8 pin plug, pins 6 and 2; 7 and 3