on1: why 5-channel? If you are going aftermarket, just get a set of component speakers for the front (check out Hybrid Audio Technologies -- I got my set at 12velectronics.com), a sub of somesort if you want that, and amp those. The HAT speaker set I got came with crossovers, so you only need a 2 channel amp to power those. I got a separate amp for the "subs", as it were.

I don't understand the need to put speakers (other than a sub/very low frequency) in the rear of the vehicle. The front soundstage is what is important. Rear fill is difficult to do right w/out time alignment equipment.

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Kirk
Las Vegas
2016 X5 40e Mineral White/Black Dakota Leather, ZLL, ZCW, ZDA, ZDB, ZPP, multi contour seats, rear side window shades, HK stereo
2011 E90M3, 6-speed manual