True, 4 pounds off isn't bad.

 

No, not too bad. But you're not going to feel or realize any improvement in performance, unless you're drag racing the car and looking to pick up a fraction of a second.
Changing from a one piece steel to aluminum shaft "just because" is a total waste of money. Now if your existing one is bad, and you find a heck of a deal on an aluminum one, that's different.

 

Definetly so. ill nvr swap to an aluminum just because that's something I'd do to a car I'm trying to race on a circuit. But sadly my camaro is a4