With all the talk of the new turbo Mercedes motors sometimes we forget about the potent naturally aspirated V8's and how much extra power they are hiding. AMR Performance tuned this 2008 Mercedes-Benz W221 S550 and with just software alone showed great results.

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In the low rev range peak torque gains of up to 50 lb-ft are seen. That is torque you will feel down low. Additionally, horsepower gains of up to 20 wheel horsepower are seen pretty much throughout the whole curve with peak horsepower going up by 16.4 at the wheels as torque drops off toward redline.

This Stage I ECU tune is available for basically and M273 V8 equipped Mercedes-Benz vehicle which means the 550 models produced from 2006 until roughly 2011. It is best to check with AMR Performance for your particular car.

At $669.99 the tune is well worth it: http://shop.amrperformance.com/Merce...une_p_297.html