Have you tried disengaging the Vehicle Skid Control system? The few times I have experienced this was in a situation where the rear would have broken loose had the VSC not been engaged. I have never noticed a delayed response with VSC off.

 

I'm not talking about just off the line. It's even at speed when I apply throttle, particularly in traffic. There is a general delay before anything happens. Sometimes it's worse than others. I think I'll go drive a new one and see if there's a difference.