I've been really happy with Continental Extreme Contact DWS 06 tires. Night and day road feel and handling improvement over the stock tires. Really good all around performance, including in the snow (Wisconsin winters). I have been using these tires (including the previous version) on my previous 9-3 and previous generation 2015 Regal GS. The only downside is that they only last about 40,000 with hard corning/acceleration and they are slightly louder/firmer than the stock tires.
I also changed the tire size to 245/45.
I also changed the tire size to 245/45.