how much rwhp do you think i will free up by switching from steel to aluminum, and do they really cure the vibration at high speeds? thanks, mine starts to vibrate above 100

 

You will probably only free up 2-3hp. I don't have one yet but from what most people say it cures the high speed vibration. Thats of course if the driveshaft is the problem.

 

I have an aluminum driveshaft
Its not the aluminum that stops your high speed vibration
Its the fact that most of the factory shafts were not balanced very well.
So in other words you can take your current shaft to a driveshaft shop to get it balanced and efectively eliminate your vibration, assuming it is the drive shaft.

As far as power goes i think its safe to say your gona put 3-5 more hp to the ground. I think the difference is somewhere around 5lbs of weight.
So your not gona feel it but it should show on the dyno.

Good luck Mike