What exactly is the benefit of performing this modification?

 

I believe it allows the clutch to fully engage faster. I think gm did it so the rear didnt get beat to death.

 

Is this a noticeble change?

 

The restriction was there to help save the propshaft from impacts. The drill mod will improve quick shifts. It depends on how you shift but for me, I can make a quick 1-2 shift but when I go to a 2-3 it acts like the gear is blocked. In severe cases ot clashes and does not complete the shift.
Yes it does make a difference.

 

The restriction I believe was put there to make the shifts smoother and with less of a kick which does put less stress on the rear end. The downside is that it restricts the amount of fluid that flows to the trans. I highly recommend doing the drill mod. Prior to the drill mod my car would burn the clutch up at the track after I did the mod I had no problems. It makes the clutch engage/disengage slightly quicker and helps keep your clutch from burning up.

 

how do u do the drill mod?

 

This is what I used when I did it http://installuniversity.com/install...sity/index.htm . The drilling part is really simple to do. But removing and replacing the master cylinder it can get to be a battle.

 

Getting that stupid braket to line up with the bolt holes is very tricky.

 

I have heard if you end up having real problems to just drill the holes out a little so they will be a bit bigger. That should make is a piece of cake. I am about the replace all my master/slave and replace my clutch so I get to do it all over again. Its gonna be fun