Finally got around to installing tunes into my 2004 STi. Alpine CDA7894 tuner, MTX Thunder304 amp, MTX Thunder 500D sub amp, Infinity Kappa 6.5" seprates up front, MB Quart 5.25" rears, and an Infinity 10" Perfect sub. Also did the bulb color change on the rest of the dash. Looks and sounds awesome. Completely gutted the inside of the car. Both front seats, rear seat, all plastic trim, console, etc. Deck was a piece of cake. Ran a 4ga power wire inside to a distribution block. Amps are mounted under each of the front seats. The 6.5" kappa's fit perfect using a 1/2" spacer. I originally wanted to use 5.25 kappa's in the rear doors as well but the tweeters stick out too far. The tweeters hit the inside of the door panel. Off to the stereo store to find a 5.25" coax with a flush mount tweeter. The MB Quart fit the bill perfectly. Sub is in the trunk and fits great undter the rear strut bar. The sound is incredible. Also installed lots of sound deadener in all four doors (Brown-Bread). Big project but glad I did the work myself (with help from a friend) rather than have it installed. I learned a lot about my car doing the hands on myself.