I have a buick regal gs which has a stock 3.8 supercharged. There is a diffrence between the 2 engins minus the supercharger. The 3.8 that comes with a supercharger is actully made with a diffrent type of metal mixture, I beleive there is more nickle in the metal to sustain the stress on hte motor. The non supercharged 3.8 does not have this additional reienforcment. there is alot of information about the pros and cons of supercharging the 3.8 in the buick regal fourm