Allow me to chime in here, as I own a 911 Turbo from this particular generation of 911 (i.e 1975-1989) – this is the first Gen. 911 Turbo cars from Porsche.
Firstly if it is a widebody with steel flares front and rare, the “turbo badge in black†on the rear trunk lid and a boost gauge built into the tach like this:
It is more than likely a genuine Turbo built factory car. There are many converted cars out there as well and Turbo look alikes as well that are normally aspirated.
Many Turbo cars had eventual failures of the factory and rather old technology KKK 3LDZ turbo and some owners converted them over to Superchargers which was OK, as you get the low compression motor to play with. There is no way that car had a Turbo AND a Paxton supercharger….if it does…I will change my name to PeeWee Herman and wear a dunce cap!
FYI, if this car is factory Turbo Targa, it is very rare as most Turbo cars were Coupes with a smaller percentage being convertibles and an even smaller percentage being Targas.
Hope that helps
Good luck!
Regards - Yasin