I bought the continental snow tires and threw them on my 18" boxster S wheels and ran all winter here in chi town no problem! better than my old cherokee and blazer! I also have a soft top and that wasn't in issue, car came with a heater
the car wasn't terrible with the high perf tires but I wanted more security so I say get the tires......plus the money saved will eventually go to 19" classics in my case.....invest in the car you love.....don't invest in something to get you from A to B......you bought the box to drive it.....
2005 Boxster Carrera White