As far as strength is concerned they are both good.

 

do you notice any more responsive/smooth accel/decel?

 

Mostly just the smoother engine vibration through the low to mid range rpm

 

I have been lookng into this mod, and on some other forums some guys say they have had some issues with breaking transmission mounts when switching fro the 2 piece to a 1 piece. They talked about relocating the torque arm bracket to fix the problem.

Is this only a problem if there is more than stock power (+50-100 hp) and/or a heavy right foot?

any thoughts?

 

I can't see what difference the driveshaft would make. It's the lifting force of the torque arm that wants to tear at the mount.
The Z28 only had a one piece shaft, and it's gonna eat a mount easier than the V6 will.