Snow Tires?
 

I have a 2002 Boxster and the tires on it are the Pilot Sports... they suck in any snow. Problem is, the fronts are 205/50/17 and rear are 255/40/17 so there arent many tire combinations that will fit the front and the back. Can I mix and match put 2 on front and 2 different on the rear? What tires would you guys recomend? Any input would be greatly appreciated!

Thanks,
Brent