This one is right up my alley - unfortunately.
I spun out my Boxster in May 2002 at fairly high speed, slid backwards over a curb and took out a rather large tree. Damage included basically all the rear suspension parts (from the curb), the rear bumper, exhaust, transmission housing (cracked mount point), and miscellaneous related parts.
Pioneer and West Coast Specialties took a long time to get it all back together (almost 11 weeks), but it runs and looks like new.
Since then, I have competed with this car very successfully in our AX events, taking class wins the last 2 years.
With about 62000 miles on it (about 30000 since the accident), my Boxster runs and handles perfectly. No noises, rattles, shimmies, or other indications that anything ever happened - it feels and sounds tighter than any of the new rental cars that I drive every week, and I drive my Boxster pretty aggressively.
One key item - was there any damage to the frame? If not, then your car should be repairable like new - if done by a good Porsche-knowledgeable shop, using the right parts. Pioneer and West Coast Specialties checked mine every which way and determined there was no frame damage or alignment problems before they started to do any repairs.
I am stunned that you got 24000 miles on the tires (of course, I go through withdrawal if I go a month without a track event). One thing I was thinking of from the earlier posts is whether the rear tires begin to wear faster and faster (vs the fronts) when the tread wear gets past a certain point.