Where in Chicago are you? I'm up in 60060.
I haven't pulled the trigger on the Stinger (yet), but the big draw for me is the warranty/maintenance. All the cars you mentioned are nice (actually would be great for the weekend toy you mentioned you were now going to get) but for daily use it is really hard, for me, to justify the upkeep. I currently drive a 2010 335i xDrive. Great car, love it, perfect year round vehicle for our area. To replace with a new 3 series (technically I can't right now because the new 6cyl isn't out nor can I get a 6 speed manual) , I'd be looking at 65k+ and then be in the same boat with maintenance in 3 years. I had it tuned was putting down 375hp, fun car. I've actually taken the chip out so that I don't have to worry (as much) about blowing the turbos or clutch. Even with my great independent mechanic, every fix is now at least $500.
My advice (take it or leave it), get a good, reliable, nice daily (aka Stinger) and if you are lucky enough to be in a position to have another toy, get a crazy car for that. 40K buys a lot of fun car that you don't need to worry about reliability (Porsche 911 Turbo anyone?).