Originally Posted by Transfer
You could but that's kind of goofy and *may* have weird handling characteristics due to two different tires. I wouldn't do it, but I can't think of a major reason why you shouldn't. Honestly the Dunlop Wintersport 3D should be about the same as the PA4 for traction and performance. The 3D may even be better, we just don't know how the PA4 performs in snow/ice because there aren't really any reviews out on them. I have a set of PA4s on my car but it's only been rainy here so far.
If you're not already too attached to the wheels, but you really want the PA4s, consider a square 18x8 or 18x8.5 wheelset.
Running four front wheels for winter on the M3 is perfectly fine and quite common!