[JimC]

The aluminum drive shaft doesn't give you any more horsepower - what it does is allow you to use what you have more efficiently because the engine doesn't have to work as hard to get things going. The stock driveshaft is pretty heavy, and the aluminum I think was about 18lbs (can't remember for sure) but it takes a lot of the rotating weight out of the assembly. The thing I noticed was that the car actually felt "lighter" on acceleration. And it did improve things greatly. I went out the next weekend after installing it and posted a new personal best at the track, shaving almost 0.2 off my time.

It is a performance gain, not a horsepower gain.