The 1-piece driveshaft for the Subaru Impreza WRX with 6-Speed transmission conversion is a complete 6061-T6 3" aluminum shaft that is approximately 1/2 the weight of the factory 2-piece driveshaft. The 1-piece aluminum shaft features larger, replaceable and greaseable u-joints and can handle about 650WHP and 155 MPH. By removing the factory 2-piece shaft and installing a single shaft the car will feel more responsive due to the lighter weight of the shaft and also the fact that the hanger bearing is not moving up and down during acceleration. Available for most popular motor/trans combinations, if you don’t see yours listed, custom shafts are also available. Please Note: This driveshaft is rated to 650WHP and a top speed of 155MPH and is not recommended for use above this speed. This aluminum driveshaft is 3" diameter and your vehicle may require some minor modifications to the driveshaft tunnel in order to ensure proper fitment. Make sure there is at least 3/4" clearance around the driveshaft before use, and that the differential bushings are not worn as this can cause damage to the driveshaft. Damage caused by improper fitment will not be covered under warranty.