From ECU tuning to differentials, we have your Mercedes products covered. GoodSpeed is Arizona's largest stocking RennTech distributor, and it doesn't stop there. The team at GoodSpeed has built more Mercedes-Benz from mild to wild than any other AZ performance shop, period. Super charger upgrades, Custom fabrication, Software tuning. And at GoodSpeed we use the only Mercedes approved dyno available. (MaHa)
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Featured Products

  RENNTech ECU Upgrade CLS 550ECU:54.219.CLS550
Our proprietary ECU upgrade for the Mercedes M278 engine in the new CLS 550 offers huge gains in performance across the entire RPM range without sacrificing around town comfort or daily driver reliability. Our ECU tune offers the biggest performance gains on the market translating to an astonishing 530 HP and 606 lb/ft at the crank! GSP Price:
$1490.00

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  RENNTech ECU Upgrade for SLSECU-TU.54.197.SLS
RENNtech tuning software for Mercedes offers significant gains in horsepower and torque across the vehicles entire power band. By modifying ignition timing and throttle mapping, optimizing air/ fuel ratios, increasing the engines rev limiter and modifying boost mapping for turbo charged vehicles, RENNtech performance software unleashes your Mercedes true potential. GSP Price:
$2945.00

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  RENNTech SLS Carbon Fiber Front SplitterAero:88.197.10.10
This carbon fiber front splitter integrates flawlessly with the original lines of the vehicle while boosting the overall testosterone level of the sporty SLS. RENNtech's one piece front splitter flows seamlessly into the front apron and is a simple, bolt on component which improves vehicle aesthetics and increases front end down force. All this while still maintaing the same approach angle as the OE front fascia so the RENNtech splitter retains the same clearence for parking stops and steep driveways. GSP Price:
$2980.00

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  RENNTech SLS Carbon Fiber Rear DiffuserAero:88.197.20.80
Our rear diffuser is the companion component to the front splitter and functions to decrease drag and increase down force by improving the underbody airflow and its transition to ambient air. As with the front splitter, our rear diffuser is manufactured using the high quality pre-preg carbon fiber and is a quick and easy install that requires no modifications to the SLS's rear bumper or underbody. GSP Price:
$3980.00

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