let commonCars = cars.filter( item => cars2.findIndex( car => car.id == item.id ) >= 0 );

// RESULT IS:
[
 {id:2,make:"Ferrari",model:"F8 Spider",price:262000,colour:"giallo modena"},
 {id:5,make:"McLaren",make:"New GT",price:203000,colour:"helios orange"},
 {id:6,make:"Ferrari",model:"F8 Spider",price:262000,colour:"giallo modena"}
]