R2 Performance Package for CLK 63 Black Series (C209- 571 HP / 533 LB-FT) bmw-x3--e83---2003-2010--esr8995031 the factory settings do NOT

the factory settings do NOT allow the valves to fully open unless certain speed and/or RPM have been reached

We have found the M176 engine stock performance numbers vary from the baseline figures claimed by Mercedes-Benz

GL 450 (X166- M278 Biturbo Engine) Stock Performance:

Performance Tests: Vehicle Upgrades 0-60mph 0-100mph 60-130mph 1/4 Mile ET Trap Speed W222 - S560 Sedan Stock w/o Launch Control

Our proprietary Bentley ECU upgrade offers rock solid performance from RENNtech

R2 Performance Package for CLK 63 Black Series (C209- 571 HP / 533 LB-FT) bmw-x3--e83---2003-2010--esr8995031 the factory settings do NOTR2 Performance Package for 209 CLK 63 AMG Black Series. Includes ECU Upgrade and Carbon Fibre Air Box. Up to 571HP and 533LB FT. RENNtech performance package 2 includes our proprietary ECU tune in addition to our full carbon fiber airbox, 82mm throttle body kit and RENNtech stainless steel headers for a gain of +53 HP and +68 LB FT over stock. Performance Package 2 Includes: RENNtech ECU Upgrade Full Carbon Fiber Airbox 82mm Throttle Body Kit