M030 was a factory option code referring to SPORT suspension. Due to United States vehicle height regulations, 993 cars sit about 30mm higher than European spec cars.
These are European or ROW (Rest Of World) spec springs that will drop the US ride height by M030 suspension by 30mm.
These will fit C4/C2/Turbo.
Front Part#: 965 343 531 01 504
Rear Part#: 993 333 531 16 504