Note the 10" subwoofer enclosure on the left side of the trunk and amplifier rack underneath the trunk ceiling.
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2011 135i DCT, Titanium Silver, Black Leather Interior, Premium Package, Aluminum Trim, JB4, ETS Charge Pipe, BMS Air Intake, Forgeline GA3 3-piece Forged Wheels 18", 18.5 front 19.5 rear, Fully Active Stereo with Audison Bit One Audio Processor, 2 PPI 500w Amps, Focal Door Speakers and Tweeters, Hertz 300W Subwoofer side trunk enclosure.