+1 on the euromotorspeed double din kit
Made things pretty smoothed, one thing I did order in advance was the double din surround trim instead of cutting the original surround trim.
took about three hours but I was taking my time, removing stuff and then reposition my AC and such.
They provided great directions and all the connectors needed to match up from new HU to OEM connections.
attached is what I am talking about with regards to the trim I replaced (red in photo) link also is for the double din kit.
http://cgi.ebay.com/03-04-PORSCHE-986-BOXSTER-DOUBLE-DIN-INSTALLATION-KIT-/220701244327?pt=LH_DefaultDomain_0&hash=item3362d1bba7#ht_1954wt_1141