One other thing in favor of BMW to me.
If you drive by a cop at 90mph with your laser interceptors jamming the speed reading, the cop will either think he missed you and give you benefit of doubt, or he may know you're up to something and ticket you with a visual estimation if speed (or plain lie).
You are more likely to get benefit of doubt with a 5 series.
2014 Porsche 911 Turbo S
2015 Mercedes C300 4MATIC