[husker boxster]

You have lots of good questions and an interesting situation. Here's my $.02 on some of your questions:

Your annual budget of $1500-2000 is reasonable. That should cover most of the maintenance on nuisance things. That would even cover an RMS repair, but not IMS.

Porsche parts are expensive period. Expect to pay 2-4 times the cost of "normal" parts. But Porsche isn't any more expensive than other luxury cars, so if you've owned other expensive cars, the price shouldn't be a shock to you. Many Boxster owners move up from Miatas, MR2s etc and it can be eye popping when purchasing Porsche parts. Just part of the price of admission into the big boy's club.

You don't mention if you are mechanically inclined. Boxsters are relatively easy to work on (sometimes you need small hands), and there's lots of info available to the casual mechanic thru this and other forums or with a Bentley manual. You could save yourself quite a few dollars if you do some of the work yourself.

Or if you're not into greasey hands and skinned knuckles, you could look for an independant mechanic who works on Porsches. This will also save you a bunch of money vs taking it to the Porsche dealership. But beware, not all indy mechanics are honest - read the thread on the poor luck someone had in Atlanta. Check around, ask other Porsche owners, and be sure the person is good before you leave your baby with him.

Finally, something you might want to consider is looking for a Certified Pre-Owned car from Porsche. They will CPO cars in the vintage you're looking for. It'll probably cost you $2K more than a non-CPO (about a years worth of your maint budget) but you'll have 2 yrs of coverage. It's not bumper to bumper but covers the things most Boxster owners fear. I traded an 01S with 43K mi in on my LE and the dealer CPO'd my trade-in. Check the Porsche dealer's websites for CPO cars.

Don't know much about Honda S2Ks, so I'll leave others to comment about them.