While the X5 ULM looks pretty from the outside, the guts are what hit you under the belt. The remote-operated doors slide out about 27 inches from each side of the body-an action that also deploys the X5 ULM's two Versus-brand seats (one for each seat assembly). After sitting in one of the Motostyle-upholstered, suede and leather seats, the driver or passenger can slide into the vehicle's radically altered, center drive position, right in the sound system's multichannel sweet spot.

Sitting inside the X5 ULM is like waking up from a knockout punch, thanks to the optically transmitted, full-resolution audio excess delivered by the DVI-9990 DVD/Audio/CD tuner installed in the steering wheel. The SPX-Z18T three-way component speaker set is arrayed in front of and beside the listener, with the woofer in the dash and the tweeters and midbass mounted in custom enclosures on the outside of each door. Half of a SPX-Z15M two-way, single-channel, component speaker creates the center channel and shares the dash with the three-ways and two SWX-1022D 10-inch subwoofers. Speed info is projected onto the windshield from a Defi Heads Up Display gauge mounted on the top of the dash.

A second Defi gauge-the Link Display-dots the overhead console and indicates engine temperature, tach, and speedo. Also on the overhead are two TME-M770 6-1/2-inch touch screens.

Moving to the rear, two PXI-H990 Multimedia Manager digital processors provide 16 channels of discrete output to the sound system. These processors also offer Road EQ, which combines real-time samples of acoustic environments inside the vehicle with equalizer processing to cancel out unwanted noise and optimize the audio. Both the processors and the DVI-9990 use the IONBUS all-digital multimedia bus. Beside and below the processors are six MRV-F900 four-channel amplifiers.

Two more SPX-Z15M speaker sets occupy the rear pillars. The other half of the SPX-Z15 set from the dash is mounted to a curved arm attached to the rear window and extends over the amps and processors. A KCA-500B IONBUS-to-Ai-NET bus connector plugs the SIR-ALPI Sirius Satellite Radio tuner into the sound system. Sealing in this audio boxing ring is a fixed acrylic window that replaces the X5's factory rear door, offering onlookers a ringside seat and creating a tightly sealed interior for maximum audio assault.

Monster Cable provided wiring for the entire system. Meguiars color sanding and buffing products put the final touches on the custom paintjob, and Oakley protective eyewear and clothing protected the two builders from installation mishaps and fashion faux pas. Should you bump into the X5 ULM on the show circuit, take some time to enjoy Alpine's heavyweight contender in the competitive mobile audio arena.