You should expect quicker steering, because of, as you said, no more flat spot..
That seems contrary to your "lag" comment... but, don't worry, whatever difference you will get used to it..
Be very careful for the first 50 miles or so.. until you wear off the slippery "mold release' coating that comes on new tires...
One more thing,.. check your tire pressure,.. they often over-inflate to seat the tire and then forget to reduce the pressure to spec...
.. around 30psi, depending on weight, is in the ball park...
...
note.. The "lag" you feel, may be additional grip from the fresh rubber instead of old, dead rubber ,.. but, remember, the tires will still be slick for about 50 miles... so careful on the corners... (I sometimes even tie a piece of ribbon around my throttle grip to remind me to take it easy for a while with new meats)...