I am very impressed. The big difference is low-to-mid range punch. The dealer did an exemplary top-notch job. Kudos to Star Motor Cars Aston Martin/Lotus service manager Les Costales who is very professional, enthusiastic, informative, and courteous. I encourage any Loti owners in the Houston area to avail themslves of service needs with Les. He sold me the kit for Lotus's suggested list of $4950 and charged $1358 for labor which was very reasonable considering the flawless and problem-free installation. I know you can get after-market superchargers that will produce more bang for the same or less buck. But, based on my sixties muscle car experience with my 1969 Z28 Camaro (yes, I'm THAT old!), factory Chevrolet racing parts never failed me while aftermarket parts always had their problems. The Lotus factory supercharger kit is specifically designed and tuned for the Elise and passes CARB standards. Bottom line, I opted for quality, compatibility, and reliability over extra HP. I can't belive that these aftermarket tuners know more about Loti than Lotus engineers. Richard Parriment, who is a member of Classic Team Lotus, agrees and shakes his head at how us Yanks toy with such a finely tuned car as the Lotus.