[lkchris]

Most 2007-2002 with the copper wiring--not fiber optic like 2003-4--featured option code 490, which gets you a 4X40 auxiliary amp and woofer speakers in the doors.

So, it's not just "plug and play" to install an aftermarket head unit.

That said because many aftermarket units advertise greater than 40 watts per channel and you're likely not inclined to run amp out connectors to the original 40 watts auxiliary amp.

In addition, the original 4 channel auxiliary amp devotes two channels to the door speakers and includes a crossover circuit that only sends bass tones to the door speakers ... which are woofers. Those woofers wont perform as you wish with direct wiring from your new head unit. You may have noticed that the fader control on your original radio does nothing ... that's because you don't have rear speakers. The door woofers are not rear speakers.

The complete factory installation would have included rear speakers in the rear parcel shelf, which was yet another option, very much seldom ever ordered.

Note that your original radio is a made in Germany Becker, standard on Porsche, Mercedes, and Ferrari in the era and very likely a higher quality unit that you'll find in today's aftermarket.

In the era the 911 (996) came with the same radio and standard with rear speakers (also the door woofers) and the auxiliary amp was 6X40 and there were different versions of that amp for coupes versus cabrios. The fader works when rear speakers are present.

A really nice setup for your Boxster is to install rear shelf speakers along with the 6X40 996 auxiliary amp, cabrio version. I did this, and the door woofer performance was increased along with the rest. As it is, you don't have speakers suitable for an aftermarket head unit and that would be an additional expense and it you are interested in sound you would want the rear shelf speakers in any event. It's pretty easy and successful and more economical to find the 911 amp on eBay and install the rear speakers. It's likely all you need.

Note: your original wiring harness radio to aux amp already includes six channels. You just need to identify the amp output to speakers terminals for the rear shelf items and add them to the amp out connector.