Did you read the Michael Sheehan's March newsletter on ATR and Carbon Fibre chassis use in the 16M/SCUD but not the 458? Just possibly the SCUD uses more advanced chassis technology than the 458...
FROM MARCH 2012 MICHAEL SHEEHAN ARTICLE:
Ferrari followed the McLaren F1 in 1995 with the F50, which was built on a carbon-fiber tub by ATR Composites, which is near the Ferrari factory. The F50's price was half the McLaren's, but its weight was 2,700 pounds. The Enzo followed in 2002, but weight jumped to 3,000 pounds.
Carbon was now everywhere in the world of high-end exotic cars, and ATR built tubs for Ferrari, Lamborghini, Porsche, Bugatti, Peugeot and Maserati. Alas, ATR grew too quickly. When Porsche slashed production of the Carrera GT from 1,500 units to 1,270 units, ATR was hopelessly overstretched and thrown into bankruptcy. Ferrari and Lamborghini were forced to take partial control of ATR to continue production, but the demise of ATR slowed Ferrari's carbon fiber planning and explains, in part, why the latest Ferrari 458 uses what is now old-school aluminum technology.