I contacted Becker and explained my stock radio with amp and door speakers and asked for the cable to install rear speakers and the radio removal tool - Total cost of $89.98 including $16 or so in shipping. The parts arrived but the cable was not the correct one (if there even is a correct one), so I got permission to return it and spent $6.50 for Priority Mail insured to get it back to them and they received it on December 8. I ended up wiring the rear speakers with some Radio Shack connectors.
After several requests for a credit, Becker credited my card today (11 days after they received the returned part) in the amount of $55.25. A 15% restock fee I guess.
Voila - Total spent was $89.98 plus $6.50 minus the $55.25 credit = $41.23 for the radio removal tool that I could have gotten on ebay delivered for $6.30.
I'm thinking that this is the required hazing from a Porsche part supplier for a newbie Porsche owner. Sure gives me a warm fuzzy feeling.