Hi,
I had no issues at all with the SL fitment tyres, but they were a good set throughout which may make a difference. The only thing I thought is that perhaps it looked a little over tyred on the car, or you could just think it looked nice and chunky! Of course in theory the rolling diameter is approx 2% greater which will affect the speedo slightly but as I understand it that would probably make it read more accurately. As you know I have just fitted some Style III's on mine but I got a full set of correct size tyres, which personally I think look better on the car. My new wheels are also SL wheels so same size as my previous turbines therefore 1/2" wider front and rear.
What do you mean by squirm a little? What tyres are they, have they still got plenty of tread?