Finally got around to try to install the amplifier and to my dismay, the Alpine MRP-M500 amplifier doesn't fit in the floor space by the L side of the spare tire and access panel. Some other folks got it to fit, but I think with my nav, CD changer, and iBus controller, the current space is about 1/8" a bit too tight in depth and I don't feel like grinding any part of the unibody down. Will have to wait a few more days to get a new amp: probably a Kenwood X500-1 (7 3/8" depth) or MTX TD500.1D (5 9/16" depth) (both 300W RMS x 4ohms). Both will easily fit in the space (measured 3x to make sure).

Nonetheless, the subwoofer and amp wiring all installed and ready to go...