2006 Mercedes Benz CLS

When Brent Khelawan wanted a show-worthy system in his new 2006 Mercedes Benz CLS, he made some phone calls and ultimately tracked down Tom Bostic, the guy behind the MTX Jeep featured in these pages last year and seen in the 2006 Car Audio/Mobile Dynamics calendar. Bostic had also done a few installs for Khelawan before when he was a customer at Bostic's shop.

Since that time, Bostic sold his shop and had gone on to work with MTX, building show-caliber systems for the company's demo fleet. Not long after, he found himself in an unusual spot: working for a Nissan dealership.

But not any old Nissan dealer. Bostic found himself in the direct employ of a "car freak," a dealership owner who through his enthusiasm for high-performance - and knack for making a buck - set up a veritable one-stop shop at Frederick Nissan in Frederick, Maryland.

Bostic says you can buy a new 350Z at Frederick, let it meander awhile through the bays and booths within the dealership and come back to a twin-turbocharged, 1,000-watt, Funkmaster Flex showkiller. It's unusual, at least in Southern California, for a dealer to get involved in tuning at that level. But it's a savvy move for anyone somewhat attuned to the high-performance aesthetic.

We could understand if Bostic were showing us a new 350Z, or perhaps a new Infiniti. He does, in fact, have his work lined up for a future feature in CA&E for the dealership owner's Skyline. But a Benz?

Bostic clarifies that he's not limited to working on Nissans at his gig. Anyone that wants a solid A/V system is welcome. So it was that Khelawan tracked down Bostic at his new job and asked him for another show-winning system, this time in the new Merc. But he also had some boundaries for Bostic.

Factory Unorthodox"He wanted to keep the factory head unit and the integrity of the factory system," Bostic says. "And the factory system, the speakers, actually sounded pretty good. But it's just lacking on that low end. Brent just wanted to add some subs and also display videos at shows."

He also wanted to win, something he'd grown accustomed to with his previous cars at DUB and Funkmaster Flex shows, and knew he'd need some kind of installation detail to set him apart. He settled on a bizarre center-channel arrangement, with dual center channels "stacked" in the rear seat area. One mid and tweeter combo blast from the rear seat armrest area (which had been converted into the popular European "ski bag" pass-through slot), with another set playing from the middle of the rear deck.

From the photos, it doesn't look like it could sound that good, and Bostic allows that the application is more design than sound quality.

"Yeah, we tried to talk him out of it. I suggested we do something cool on the rear deck, something with some stereo spread. It's odd to have one on top of the other like that. But he had his heart set on it. He really wanted more sound coming into the cabin, so you've got the two component sets broadcasting. And it works for him. He doesn't have to turn the system up as loud. And the pieces look pretty cool when they're all lit up."

Sturm Und DrangTo keep things streamlined, Khelawan opted to keep the factory Harman Kardon components in the doors. The only additional speakers are the center channel component sets and the dual 12" MTX Thunder 8500 subs. The center channels are run off of a single MTX Thunder TA3404 4-channel amp, which is downstream from the factory 4-channel amp. In similar fashion, the factory subwoofer amp is used as a preamp to power the dual Thunder TA3401 amps.

"The MTX amps have a line-out converter, but it's not like a normal converter," Bostic explains. "It has a lot of adjustability. It's more like an aftermarket line converter. You can adjust your left and right, times ten, etc. It's a pretty detailed converter built into those amps.

"These amps also have an auto wake-up circuit. As soon as it sees speaker level voltage coming in on the RCA inputs, it wakes the amps and turns them on. You don't have any remote leads going into it. There's also a hush circuit, so there's no turn on/turn off thump."

In this case, the configuration worked perfect, Bostic says. "There was no need to go into anything else, because you're keeping the factory amp in there to run everything except for the sub. So we tied into the rear speaker outputs of the factory amp and ran those into the MTX amp, and that allowed us to gain everything - as much as we needed to - to keep it equal to the factory rear speakers. It's the same thing with the subwoofer. His sub volume control is still functional from the head unit."

The one requirement for any show car these days: Video. Lots of it. Khelawan has five screens scattered throughout the CLS. There are two 9-inch Eiger Vision monitors in the trunk lid, two Eiger Vision headrest monitors, and the factory screen up front - converted to useful monitor through a NavTV unit. A Sony video switcher in the glovebox allows Khelawan to run four different video inputs.

Sources include an Xbox, a Clarion six-disc DVD changer, a video iPod and the factory nav source. Additionally, each headrest monitor has an independent video jack for plugging in handheld game units or additional video iPods. The biggest feat for Bostic however was keeping the Merc's active-headrest-restraint system intact.

"We spent about eight hours figuring out how to keep it. So instead of cutting everything out of it, we basically built a little shroud around the outside and mounted [the monitors] directly to it. It didn't mess with anything inside of it. The tubes were hollow already, so we could run the wiring through it.

"It was a little bit of drama trying to figure out how to make sure that once you take it apart, you can put it back together and it'll still function. There's a bunch of little gears in there. There's more stuff inside that headrest than you would believe. It's ridiculous. There's more technology in it than some cars."

Merc ScanThe final test came when they took the CLS up to the local Benz dealer and had the techs run a scan tool on it. Since the restraint system ties into the airbag system, if anything were afoul, the system would throw a code. It didn't.

Bostic admits that the work on the CLS isn't groundbreaking. But that was the point. This wasn't a car meant to be gutted. Khelawan was clear about that.

"It's fairly straight-forward," Bostic notes. "It did what it needed to do. It looks cool and sounds good, and that's all he wanted. It's a cool car, looks great, has nice wheels. Brent spent the money in all the right places. It's not any super-spectacular, sound-quality-winning system. It was made for a different purpose."