Yep. Pull the cardboard cover from the trunk and you should find a spot. If that doesnt fit your plan pull the wood from the pass. floor and check there, I believe the is a space there for power wires.

Great, thanks! Does anyone know how much room is under the rear deck (where the rear speakers are)? If I were to use a sub, I could use a shallow-mount under the seat or rear deck
if the space is available.

I put a set of 4 Reference speakers in my 85 and they fit into the existing speaker holes perfectly, even the screw holes matched! (the tweeter on the rear Speakers don't allow for the grilles) I can't remeber what size they are but they probably are the same size as the stock ones. Also put in a alpine head unit and a 10'' sub. The sound is amazing. Best of all, I got the whole package at Best Buy!

The front trunk is a great place for a subwoofer, also anything bigger than 12'' won't fit. I've got a 10'' and it is more than enough bass

When I purchased my 82 Targa 8 years ago it had 28,000 miles
and the orig. Blaupunkt system...which was horrible. I would rather listen to the engine, but this car is for road trips & my wife wanted to listen to tunes.

I upgraded to a system from Rod Birch. No cutting of door panels, ugly trunk amps or big 6x9 speakers sitting on top of the
panel beneath the rear window.

The car has a great sys, removable sub-woofer enclosure behind the seats, amp under the drivers seat. Looks factory installed
Did I devalue my car?
Not sure, but it's not for sale , so I don't really care !

Check out Rod's site, he has done 100's of systems on all models of 911's

http://www.caraudioinnovations.com/porsche.htm