Why do you want to change our your OEM drive shaft with an Aluminum Shaft? The answer in part is referred to as "Unsprung Weight"
"Unsprung Weight" is weight that is not supported by the suspension of the car. This usually includes the the weight of the wheels and tires as well as a percentage of the weight of the suspension itself, including control arms, anti-roll bars, shocks, struts and a portion of the drive shaft. Reducing unsprung weight is the key to improving handling. The lower the unsprung weight, the less work the shocks and springs have to do to keep the tires in contact with the road over bumpy surfaces. An easy way to reduce unsprung weight and improve traction is to replace stock components with special lightweight components.
An Aluminum driveshaft from PST is manufactured from 6061-T6 DOM (drawn over mandrel) tubing which provides the most concentric Aluminum driveshaft available. High strength aluminum tube yokes are Mig welded with less than 10 thousands total run out. The aluminum driveshaft is balanced to less than 1/4 oz/in to assure vibration free operation.
You probably already have a shaft waiting to be installed but if you don't, PST has a great section on their website called Driveshafts 101 This tutorial will provide a solid knowledge of all the information you will need to provide PST for a driveshaft to be manufactured to fit your vehicle properly.
To start, this is one job that is made significantly easier if the car is totally off the ground, but not necessary. If you don't have access to a lift, raise the car as high as possible and support it completely with jack stands. Once the vehicle is secure and safely supported, you want to remove the 4 bolts that mount the OEM shaft to the differential. Clean any thread locking material from the bolts with a wire brush or wire wheel on a bench grinder.
Have a pail available to catch some transmission fluid that will escape from the tail stock of the transmission.
After removing all of the bolts and setting them aside for re-use later, use a screwdriver or small pry bar, wedged between the bolting flange and the U-Joint and force the OEM shaft towards the transmission. The yoke will slide into the tranny far enough for the driveshaft to clear the bolting flange. Lower the shaft near the differential enough to clear and slide it towards the rear of the car. The yoke will slide off of the splined tail shaft of the transmission. Be prepared, the drive shaft will fall away so you will want to be prepared to support it, and you will loose a little bit of transmission fluid out of the tail stock. Don't allow the driveshaft to drop to the ground, you could bent it or cause an out-of-balance condition making the OEM shaft useless if you ever needed it in the future.
The new shaft goes in with the reverse steps that we have just completed. Wipe down the new yoke to ensure that it is free of dirt, grime and will not damage the seal in the tail stock of the transmission. Align the yoke with the splined shaft and push towards the front of the car. You may have to rotated the shaft slightly one way or the other to get the splines lined up.
Slide the shaft yoke into the tail shaft of the transmission enough so that the opposite end will clear the differential mounting flange. Line up the driveshaft flange to the differential flange by rotating the wheels slightly, then slowly pull the shaft towards the rear of the car until the two flanges mate together.
Replace the 4 OEM bolts with a small strip of new thread lock and tighten gradually by using the Cross Bolt pattern. Torque these bolts to 75 ft/lbs. You are now ready to lower the car off the lift or from the jack stand and take it for a test drive.