I agree with MC. I have a 1970 Alfa and the 3.4 996.... and I never thought it would be the Porsche I would be worried about in traffic....
If in a lot of traffic mine will go above 100. At Anglesey last summer I got to 110 on track and that was having had new rads, new coolant, new water pump, LTT, and Revolution confirming that both low and high fans work. I've since fitted a third rad and it seems fine on track and when moving, just doesnt seem to keep cool in traffic.