The initial S2/S4 series, gen 1 from 1993, is the 'original' Audi quattro model.
Its got the single turbo charged five cylinder engine mounted longitudinally with the majority of the engine being in front of the front axle line...talk about a difficcult engine location...well the 911 manages as well. To get the most out of it I find that a similar driving style to the 911 is the best, get the braking done nice and early in a straight line, and apply power before the apex to make sure any understeer occurs once you are 'thro' the curve. Cannot take too much speed into the curve without risking a washout from that weight up front..
I have a the S2 wagon, with its 230hp and 258lbs ft as a daily driver and it does need a firm prod to get going, but fly it does....
Around town its great 'cos nobody knows what it is and if you want you can trundle around in complete amonimity but if you need to get moving its a prod away...scare many 911s quite easily
Great car, but for all its speed it is no sports car.
Tried the later versions including the RS4 and the same applies, they get even quicker but they do not get any sportier.