My first car was an 02' audi A4 in beautiful denim blue, anyways... I had this car pretty modded, about 220 AWHP and had a set of h&r/ bilstein for shocks and springs, and a nice thick swaybar in the rear from the RS4, needless to say handling was sublime with my 235s Falkens all around.
Tight corners on this car was effortless, and the car simply would not lose traction. When it would lose traction it wouldn't be so significant as to cause any alarm, and this is with TRACTION off. This car with traction off can be safely and confidently be taken into a sharp turn at a relatively high speed without fear of the the rear of the car giving out. Quick turns sometimes were boring, and the car is very behaved. So it may kill some of the "fun factor" but I most certainly have more confidence, and the car is very predictable if i would lose some traction on say a sharp turn. It is what I'd call "tamed"
The RWD 335i i know drive, is a big move in regards to about 100+ more HP and the rear wheel drive. I must say BMW does wonders in terms of handling, compared to my old car. Especially with a nice set of rubber, on a hot day. Car handles phenomenally, smoothly, and is completly glued to the pavement. But in regards to driving the car HARD with traction off, it is just you and the animal, no help, and the car is very quick to lose traction even on those meaty 255s, and the back would give out. Sure a little power drifiting is fun, but sometimes it can reach a point not within one's control and there you go into the guardrail.
Audi's quattro IMO is impeccable especially when coupled with suspension and sway bars.
I can only imagine what the BMW will be like when I get that done to the car as well. All in all, BMW may be a funner drive , but audi's driving is a lot more tamed, laid back, and I would have to say more safe.
This is the exact same way that Jeremy Clarkson felt about the e46 m3 vs b6 s4 in