Excepting the steering kicks caused by a bumpy track, you can basically break down what's doing in each corner in to 3 segments...
Turn in
Unless the car is already loaded laterally in the opposite direction to the turn (due to the car transitioning from a previous turn) his first steering input is almost always smooth... though this initial movement may be very brief, it's still smooth to ensure he doesn't overload the outside front tyre and create understeer. Because the car is right on the grip limit, and he's using trail braking, the car is most often starting to slide neutrally once the inital action of initiating the turn is started - though in some corners he's getting a bit of turn in understeer and other a bit of oversteer, depending on how accurate he is with his trail braking, entry speed and steering input. This means as soon as he's initiated the turn he needs to use the steering to balance the grip front and rear... winding minute amounts of lock on and off rapidly to maintain a neutral balance.
Mid corner
Almost always a constant steering angle unless he's riding the kerbs, or there are bumps - easiest to see in the longer, constant radius turns, where understeer is the primary handling trait.
Corner exit
In the GTR, the rearward torque split coupled with how early (usually just after the apex) and how hard he's getting back on the gas mean's he's generally getting a bit of oversteer... so he has to wind the lock off quite quickly to handle the rapid change from mid corner understeer to exit oversteer. The GTR's electronics are having an effect here too... moving torque from back to front as it senses oversteer... so there's a bit of fight between driver and car for who's actually in control.
At the Nurburgring there are a lot of quick transitions from right to left or left to right. These cause rapid lateral weight shifts and as the car is loaded he's having to manage some turn in oversteer at times, which makes the steering inputs look violent... but you need to look at the way he manages turing in from a straight in to a long or constant radius turn to see the true technique he's using.
If you watch this video you'll see there's far less 'sawing' at the wheel on the initial turn in... yes, occassionally, he gets a bit of understeer, meaning he has to add a bit of extra lock quickly to get the car turned in, but most of the time his inputs are smooth and measured. Of course a car running on slicks with lots of downforce will generally slide less and so will require less steering corrections. Most of the short, sharp inputs in this video are caused by the bumps kicking back thorugh the steering...
