Congrats!
96,000 miles in just over four years.......that's about 22,600 miles per year. You must do a lot of highway driving, which is less stressful on the engine than short-trip, city driving.
At 250,000 miles, if you're not ready for the 996, you can always pick up another Boxster at under 100,000 miles an do it all over again!
TO