I have gone for a pure SQ system in my 2000 Chevrolet Blazer.
SOURCE UNIT:

McIntosh Labs MX406 Control Center
The true and tested MX406 source has been a current unit for McIntosh for 7 years now. The source is very simple and gives a super clean and classy look to the dash. What integrates the unit so well is the fact that McIntosh extended the face panel in order to cover the space traditionally occupied by aftermarket trim rings. The unit is installed in a Metra dash kit.
AMPLIFIERS:
McIntosh Labs MCC404 Speaker Amplifier (4x100@4ohms) and a McIntosh Labs MCC302 Subwoofer Amplifier (1x600@4ohms). The MCC302 has a McIntosh R1163 remote gain control attached.
The amplfiers are set in a vinyl wrapped MDF amp rack (the cover is off in the picture) in the front of the cargo area directly behind the seats. The amp rack has a set of shelves on each side. An Alumapro CAP 5 Capacitor/Distribution Block and Relay call the left hand shelf home, the small relay resides on the floor under the left rear passenger seat. The original coin dispenser in the center console was broken down and refaced with a piece of black plexiglass to house the remote sub amp gain control. As a result the gain's housing snaps right into the factory brace for the OEM coin dispenser.
SPEAKERS:
Front Stage:
Dynaudio System 240MKII 7 and 1 inch component set.
Rear Stage:
McIntosh Labs MSX485 5 1/4 inch coaxial set.
The Dynaudio MW160 midwoofers and the McIntosh MSX485s were affixed tightly to the factory baffles using MDF rings. The Dynaudio MD100 tweeters reside in the factory tweeter locations in the dash. Not the ideal place for staging but my top priority was to maintain the OEM look.
The passive cross-overs for the Dynaudio Components and McIntosh Coaxials reside underneath the center console. I wanted to keep the Amp rack nice and simple and the doors were not an option (in my experience crossovers can get pretty beat up when installed in the doors.) There was a suprising amount of room under the console. I ran all of the speaker cables from the speaker amp underneath the carpet and brought them up through a hole that I produced in the carpet that is now concealed by the console. There is a ton of stuff under the console and all of the original storage compartments are still in tact. I have removed the center console storage compartment to show you one of the McIntosh Crossovers and one of the Dynaudio Crossovers as well as a mess of speaker wiring (out of sight out of mind). The other two crossovers reside further inside the console.
Subwoofer:
Alumapro Alchemy 12RX 12 inch subwoofer.
I have auditioned many subwoofers over the years and there isn't a brand that performs better in SQ setups than Alumapro. I decided to use a single twelve in order to keep the cargo area functional. The 12RX is housed in a custom fiberglass enclosure. It can be removed easily when I need the extra space (or if someone is compeled to steal it, YIKES!)
POWER SUPPLY:
In order to accomadate the current drawn by the pair of McIntosh amps I have installed an Optima Yellow Top Deep Cycle Battery as well as an Alumapro CAP 5 (5 farad) capacitor & distribution block. All of the power cables are from the Stinger Expert Series, the hexagonal housing really does make them much more flexible than traditional round housing. 4AWG runs from the Yellow Top to the CAP 5, 4AWG runs also grounds the battery and the CAP. Having 4AWG runs of cable would be worthless if I did not upgrade the grounds. To accomplish this I placed a two footed Stinger ground terminal on the chasis near the battery and another on the floorboard underneath the left rear passenger seat that accepts the ground from the CAP 5. To protect the cable from the battery to the CAP 5 a Stinger Expert ANL in-line fuse resides near the Optima. Positive and negative runs between the amplifiers and the CAP 5 are 8AWG.
SIGNAL PATH:
Interconnects:
All of the electronic components in the system are connected with Stinger Hyper Series interconnects.
Speaker Wiring:
All of the speaker level lines are accomplished with stinger 12AWG cables in order to provide for the least amount of resistance to the signal as possible.
FURTURE UPDATES:
I plan on integrating a new fiberglass subwoofer enclosure to acompany the amp rack. It will be covered by the same vinyl and will be contoured more effectively into the cargo corner. It will appear as an extension of the right wing/shelf of the amp rack.
Photos of the new enclosure will be posted in two weeks or so (I am saving up for a router and a staple gun for use in the install).
I am also planning on ditching my front and rear channels for a pair of Morel Elate 6 2-way comps and a pair of Morel Hybrid Ovation 6 coaxials respectively. The super hot Morel crossovers will be installed atop the right amp rack wing/shelf.
Another simple upgrade will be when I ditch the Stinger Hyper Series interconnects for a three new Stinger Expert runs (two from source to the speaker amp, and one from the speaker amp to the sub amp.)