http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=8036282256&sspagename=STRK%3AMEWA%3AIT
If you want rear speakers, you gotta buy one of these as well as the speaker kit to do it right:
http://cgi.ebay.com/ebaymotors/Genuine-PORSCHE-Boxster-Factory-Rear-Speaker-Kit_W0QQitemZ8035902794QQcategoryZ42612QQrdZ1QQcmd ZViewItem
These boxes can go for $250 or more on Ebay, and they're $500+ through the parts department at your local stealership. Just thought I'd throw that info in for buyers.
I got mine off ebay for $120 because it had red carpet. Black carpeted ones always go for more because it's a popular interior color and black goes with all the other colors well too.
I think I paid something like 249.00 for my speaker kit.