ive only test driven a 328 m-sport for 5 minutes. (and im buying one).
but i own a 2010 a4 quattro sport.
the thing with the audi is they are pretty stable feeling. like planted . the AWD is like that, but on the other hand it makes it a lot less fun. the A4 is also pretty heavy.
in corners it will understeer. i've gotten my car to slip just a little in a corner, while flooring it (yeah yeah dangerous etc, but no one was around) but it will plow badly because of the bad weight balance and the suspension is tuned to understeer for people used to "audi understeering". weight balance on a 2.0t quattro is like 56/44 or something like that so its nose heavy.
in the wet or something though, it feels extremely solid (i've never driven a 328xi, but i guess i'd imagine this is more than AWD than it being an audi). but yeah... if youa re looking at a 328i vs a sport quattro a4, then thats my impression. if you are talking an A4 sport CVT well uhd otn even buy it because thats just terrible and isnt even an audi.