I was going to post this in the sticky but dont love of some of the methods (such as drilling tweeter sails/ OEM HU replacement, when its totally not necessary).
Not to knock the install, just don't want to suggest this to N00bs as this being the "right" way to do an install/ or that these methods are necessary.
Comments from the peanut gallery? Willing to reconsider.
FS:Sub Amp - works w/ Technic harness! MRD-M300 - cheap