It is a decent kit. It does make the vehicle more fun to drive, but I have had issues with mine even before I started to change it from the original ESS kit. From what I hear it provides the largest jump in numbers for the supercharger kits available for the the 4.6. I have not have major problems with the kit, but the problems I did experience before doing some chnages to the ESS kit were failing injectors, constant SES light due to the sensors in the cats and once I lost all boost due to a faulty vacuum line. But generally it is a good kit. I have a lot of faith in vortech products.

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2007 Jeep SRT-8 (going to be supercharged)
2007 Trailblazer SS
2003 X5 4.6is ESS supercharged
2004 Silverado SS supercharged
2005 Escalade supercharged
2003 Corvette ZO6 supercharged
1999 Mercedes S600