[bhuey]

The radio is an aftermarket unit. I will assume since you asked the question about the radio that the speakers shutting off when the 'fasten seat belts' light comes was not a safety feature added by Porsche.

Other than adding a radio and an amp I am not aware of any other modifications by the PO.

There is no after market alarm that I am aware of.

Thanks for your help!
Bud