2005 Bmw 645ci Base Convertible 2-door 4.4l on 2040-cars

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Watch the BMW M4 GTS lap the Nurburgring in under 7:28

When BMW unveiled the new M4 GTS back in October, it said it could lap the Nurburgring in 7 minutes and 28 seconds. That's all well and fine in terms of bragging rights, but what Bimmer enthusiasts have been waiting for is the proof. And here it is, in ultra-HD 4k glory. In the video above, you can see the new M4 GTS scything its way through the Green Hell of the Eifel mountains. Behind the wheel is M GmbH engineer and racing driver Joerg Weidinger, who helpfully narrates the video to show us exactly how he tackled each and every corner along the 14-mile circuit. Which may come in handy for those with a season pass to the Nordschleife, but the rest of us are more concerned with that lap time and how it holds up. To put it plainly, the 7:27.88 lap makes the new GTS not only the fastest in the M3/M4 line to date, but the fastest production Bimmer ever clocked around the 'Ring. It handily beats the previous M3 CSL (7:50) and the stock M4 (7:52), and even trounces more powerful Bavarian machinery like the Z8, M5, and M6. There've been a handful of BMW-powered racers, motorcycles, and prototypes (not to mention the McLaren F1) that have clocked faster times, but as far as four-wheeled, standard production Munich-mobiles go, the new M4 GTS is the new King of the Ring. It also just so happens to match or beat the best times clocked by the more exotic likes of the Ferrari 458 Italia, McLaren MP4-12C, and Porsche Carrera GT – putting the M4 GTS in rare company indeed.

2013 Dinan S3 BMW 550i

Steve Dinan has been enhancing BMW models since 1979. But don't throw his company into the ring with the dozen or so other tuners who tweak, tinker and piggyback upgrades on the famed German marque. Dinan is a tuner, but it's also an engineering firm that writes its own software, builds its own parts and then backs everything it does with a factory-grade warranty. That sort of fastidiousness comes at a price, but most of its customers - including the powerhouse of BMW Motorsport - rely on Dinan to help them come out on top.
In stock form, BMW's 550i is a formidable four-door with a twin-turbocharged 4.4-liter V8 rated at 400 horsepower and 450 pound-feet of torque. While those figures allow it to run with quick company (0-60 in 5.0 seconds, according to the automaker), Dinan puts the sedan's kettle on full boil with its S3 package. Starting with the engine, the performance engineering firm bolts on larger turbochargers, air-to-water intercoolers, a trick strut tower brace cold air intake, a quad-pipe free flow exhaust and its own engine management software. Pump in some premium fuel, and the result is 542 horsepower and 587 pound-feet of torque. Power is sent through the stock eight-speed automatic to a limited slip rear differential (Dinan will upgrade xDrive all-wheel drive models, too).
The Dinan S3 also features and extensive suspension upgrade that includes new front camber arms and low compliance rear control arms (engineered to reduce understeer and improve turn-in). The stock dampers are retained, but new bump stops are installed along with new springs. Overall, the car rides about a half-inch lower than stock to improve roll rate. To reduce unsprung weight, forged 20-inch HRE Performance wheels are fitted at all four corners (wearing Michelin Pilot Super Sport tires - 275/35ZR20 up front and 295/35ZR20 in the rear). Lastly, the company remaps the factory Electronic Damper Control (EDC) software with its own Dinan Shockware to work in conjunction with the new enhancements.

Automakers' sound systems: Crank it, don't yank it

Years ago, one of the first things most music lovers did after buying a new vehicle was drive to an aftermarket stereo shop to get the crappy stock components swapped for better gear. And you'd typically get not only better sound but also more bang (and boom) for your buck. But in the past decade or so, the overall quality of OEM audio has dramatically increased, while car electronics became more complex, removing the incentive for most new vehicle owners — and all but the most hardcore DIYer — to start from scratch. In 2010, I did a comparison of the average costs for OEM electronics vs. similar offerings from the aftermarket, and back then automakers' stock premium systems were by far the best bargain — and are probably an even better value now. The premium 14-speaker, 1,200-watt JBL system in the all-new 2019 Toyota Avalon is a prime example of this trend. It's standard on the top two Limited and Touring trims and is available as a $680 audio upgrade on the XLE and XSE. I doubt you can even buy 14 speakers and 1,200 watts of amplification from the aftermarket for 700 bucks, much less have it all installed. And because the system is bundled with Toyota's Entune infotainment system, Apple CarPlay and a surround-view camera, removing the head unit means you would likely lose these features. Another advantage of OEMs and their audio partners is they can design the car around the audio system. In the past, automakers would typically place speakers where convenient for packaging, not for optimal sound reproduction, and audio engineers were forced to compromise. But as with the Avalon's premium JBL audio system, this is starting to change. At a recent behind-the-scenes peek for media into the process of developing the system, Toyota and Harman engineers delved into the minutia of sealing the inner panel of the front doors to create an enclosure for 6x8-inch woofers, making space in the pillars for JBL horn tweeters and extensively measuring the acoustic properties of the interior to tune the sound to the space. I'm met some creative and skilled car stereo installers, but none with a degree in psychoacoustics. The system is also the first to feature Quantum Logic Surround that creates a multi-channel listening experience from two-channel sources. And it includes Harman's Clari-Fi processing that "rebuilds key details lost" in compressed audio formats used by streaming music services and MP3s.