I actually noticed a slight improvement in signal quality...at least at my desk at work, I used to have issues with call clarity. After the ics update, the calls are clearer (my wife has not once complained that she can't hear me :) )
I had the same problem yesterday...I had to disable my firewall for the Kies update to install on my Windows 7 64 bit computer. After that, Kies update and phone upgrade went smoothly.