92-93 Mercedes Benz 500SEL Stereo Upgrade

I have a 1993 Mercedes 500SEL with the factory becker 1432 cassette head unit and the 1432 becker radio tuner in the trunk next to the bose 7 channel amplifier that runs the 11 bose speakers. The system sounds great but I want a cd changer and sirrius sat radio and wired ipod kit. Stereos are my specialty but mercedes are and all of the benz forums ive read say unless your completly removing this stereo keep it 100% stock. I dont mind keeping it stock but I want to add the changer,ipod,sat radio. Does any body have any ideas. What makes this car difficult to do an aftermarket stereo is the head unit is in two pieces. The head unit is just a cassette controller and the radio tuner is in back. In 1994-1999 S Class the head unit had the tuner in it. I have searched the web everywhere for an adapter to just replace the cassette and tuner but had no luck. Another reason for the difficulty is on the front console between the front seats there is a fadar control. The are 11 speakers: 2 in the dash,2 in the front doors, 2 in the rear doors, 4 in the rear deck and 1 center channel behind the rear view mirror. There are also 2 additonal speakers in the dash but there for the factory cellular phone. I would like to install Pioneers new 7800 head unit with bluetooth,a Pioneer 12 disc changer,Pioneers Ipod Kit & Sirrus Satellite Radio. I want to keep my factory Bose amp & speakers. Any one have any help on this install?