My goals for this project were to improve sound quality, not cut any factory wiring, and save money on gear. Mission accomplished!

Parts list:
Polk DB6501 components in doors
Bazooka ELB110RS subwoofer
Alpine MRP-F300 amp
Sirius XM Onyx radio tuner
Monoprice.com 16ga 4-conductor speaker wire
CD International satellite antenna wire

Overall, I kept the cost of the project to about $430 with everything listed above. I cut plexiglass panels in the shape of the 4" door speakers in which to mount the tweeters. I ran power cable down the passenger side to the rear hatch and speaker cable down the drivers side from X9331 to the amp, and back up to each door. I did re-wire the doors. I don't like having my crossovers mounted in car doors anymore, so I mounted everything in the trunk... I mounted the amp and crossovers to the subwoofer box itself. The shape of the Bazooka sub box fits perfectly against the back seat if you position it firing to the rear. I know, I know... Bazooka? Really? Yes. The price was too good to pass up. A complete ported box, with 10" sub, for $60, free shipping? I found it is well worth the price... more on that later. I created my own X9331 wiring harness to do the job so when the lease is up, I just unplug it and connect the factory wiring back together. I was going to use the ProClip to mount the Onyx radio, but when it arrived I decided it was just tooooo ugly. I mounted the Onyx radio in the cubby ahead of the cupholders. The antenna cable was run under the center console to the stock antenna connector under the passenger seat. A spare remote control I had from another XM radio appears to be compatible and makes changing stations easier. My stereo does have the usb and aux input, so it was convenient to attach another source.

I used the amp's speaker level inputs for this system. I tapped into the front channels only--learning from what others have said about bass roll-off on the stereo's rear outputs. I left the factory rear speakers intact, and still connected to the stereo. Overall, the sound is much, much better than what I would expect from such an inexpensive system. I don't pound my systems but I do like them loud and clear, which is exactly what this system can now do.

Aside from the box in the trunk (which is hidden, rear shelf FTW), the system is totally stealth, so there's not much to see. But I'll try for some pictures if anyone has questions about it.

 

i'd like to see some pictures. i know i want to do something as far as adding bass, but i'm just not sure what. not very technical so i probably wouldn't want to do too much myself, but am hoping to add a tube or something really simple for some extra punch.

 

For some extra punch, you won't need much. I have twice as much power going to 10" subs in my other two vehicles, so I didn't expect a whole lot from 150wrms going to this one... but I had to turn the gain on the sub ALL the way down. The mini is such a small space that you will hear major improvements with minimal upgrades.

 

How about those pictures? I'm most interested in your wiring through to your doors and your X9331 harness. I just bought some CDT ES-643's and almost ready to do the upgrade.