Considering the cost of the factory system, I'd go with a replacement stereo that has the flip up screen for navigation. They cost $1200-$2500 installed depending on the brand and quality.
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1987 928S4 Silver Metallic (980)/Navy (TP) 5-Speed
2000 Boxster Speed Yellow/Black 5-Speed
1966 Wife White/Brown Top
1986 Daughter White/Brown Top (Sold!)
1992 Daughter White/Blonde Top
John you are not thinking about the new "no din slot" Porsche dash that would require a complete redo. Aftermarket stereo systems are a no-go in the new Boxsters.
This is my only disappointment with the car. Even the Bose isn't as good as everyone would like and there's no way to upgrade it.
But when I win my black 987 next month it will have a non-bose system in it and I'll still be very happy.