Im ready to race a hemi, the supercharger is belt driven instead of gear driven. You can hardly hear it, it sounds very familiar to a alternator under a load. Its just a very soft whine, the engine and exhaust is so loud it covers up the S/C. Havent been to the track yet but hope to see 14's, when it was stock (I mean bone stock, like driving it off the lot) it ran 15.8 with a 4.8 and 3.42's , a buddy of mine has an '06 with the 5.3 and I have beat him in the 1/4 and with gas miliage. Best of 17.8mpg now with 3.73's.