; Mazda MX-5 (1st Gen) NA Original radio options - InCarTec

There are multiple original radio options in the Mazda MX-5 (1st Gen) NA, which option is the original fitted system?

Enclosed Subwoofers/ Drivers Enclosed Subwoofers/ Drivers
Extra Slim Subwoofers Extra Slim Subwoofers
Spare Wheel Subwoofers Spare Wheel Subwoofers
Underseat Subwoofers Underseat Subwoofers