wantone:
 

991 Turbo S is the high end model of a lower category series of cars that starts with the Boxster. You will obviously find less value at the high end since the car is loaded with options that have extremely high margins. 488 is the entry level supercar (of a more expensive and limited production platform) and therefore if made right it offers more value for your money.

In theory this might sound interesting. But in practice... A 488 is a 488. A turbo S is a turbo S - both are in the same league. It is a matter of taste. I, for example, don't want a 488 after the experiences I had with Ferrari. But I want a turbo S.