As an employee of BMW and Owner of Unique Customs Wheels, you won't be able to get the feel of bigger wheels unless you actually go bigger. The staggard fitment really enhances the handling ability build into the car. If you don't want that staggard look so as to gain tire life by rotating, then go with 8.5X17 or 8.5X18 all around. The tires you will need for the 8.5X18 is 245/45/17 or 245/40/18. That will give you +.138% speedometer difference. Meaning if your speedometer reads 100 mph, for example, then you are actually going only 99.86. You never want the speedometer to show a slower speed than what you are actually going. I have a web site if you need BMW Wheels and/or Tires. its www.uniquecustomswheels.com
or email me at firstname.lastname@example.org
for a quote.