[husker boxster]

Let me take a swing at your questions.

The difference between a 225 and 245 tire is the height of the sidewall. A 245 will be taller. Whether either will work will be influenced by the width of the wheel you use. I remember seeing your thread about new wheels, but I forgot what width and offset your fronts are.

As an example, say your fronts are 8.0" wide and 50mm offset (typical Boxster wheel from Wheel Dynamics). The 225 may have to "stretch" to fit the wheel, which will cause the sidewall height to be smaller than if it was on the standard Porsche 7.5" wide 18" wheel. A 245 will work on the 8.0"/50mm wheel - at least it does on the Carrera S wheels I use with my summer tires on my '01 S (I have the winters on now so my sig pic has changed). BUT, there is very little clearance between the tire and the shock spring, however it is a static distance and not a problem. Don't know if there is a difference between the shocks on a base and S Box - specifically where the bottom of the spring is on the shock. One thing I noticed with the 245 is that the height of the sidewall makes the front of my Box look high. If I had it to do over, I would go 235 and get the best of both worlds - proper sidewall height and no tight clearance issues.

My last paragraph mentions offset but doesn't get into the details. If the offset is not 50mm, a different offset may move the wheel closer to your shock and increase the possibility of rubbing issues. A shorter sidewall tire may alleviate the problem but I don't have first hand experience with a different offset.

Hope this helps. You are wise to ask before making an expensive mistake. I'm sure others can chime in with their thoughts. If I had to error one way or another, the 225 will work while the 245 should work.