Three people were arrested at a car workshop in Sils, near Girona in the northeastern region of Catalonia where four fake Ferraris were awaiting sale.
A total of 14 vehicles were at various stages of transformation from mid-range family cars into top-end sports cars.
The mechanics took second hand Toyotas and bolted a Ferrari or Lamborghini body kit fabricated from fiberglass to its exterior, adding fake badges before selling it over the internet, the police said in a statement,
The dashboard had been altered using stickers made to look like Ferrari dials.
The gang were traced after one of the cars was offered for sale in Benidorm with a €40,000 price tag.