The challenge of the Targa was unprecedented in its difficulty and the driving experience of any of the course variants was unlike any other circuit in the world other than perhaps that of the Nurburgring in Germany and (for motorcycles) the much faster but similar Snaefell Mountain Course on the Isle of Man. All of the variants had 18 to 23 corners per mile (11 to 14 corners per kilometer)- the original Grande circuit had in the realm of 2,000 corners per lap, the Medio had about 1,300-1,400 corners per lap and the final iteration of the course, the Piccolo circuit had about 800-900 corners per lap. To put that into perspective, most purpose-built circuits have between 12 and 18 corners, and the longest purpose-built circuit in the world, the 13-mile Nurburgring, has about 180 corners. So learning any of the Targa Florio courses was extremely difficult and required, like most long circuits, at least 60 laps to learn the course- and unlike the purpose-built Nurburgring, the course had to be learned properly in public traffic, and one lap of even the Piccolo course would take about an hour to do in a road car- if there was little to no traffic. To even finish this punishing race required a very reliable car- and it being a slow, twisty circuit it was very hard on the gearbox, brakes and the suspension of a car. Some manufacturers and entrants, particularly non-Italian ones would sometimes outright skip the Targa because of the difficulty of learning the layout and were unsure if their cars could stand the brutal pace there.
