New advanced electronic damper control system
reduced overall weight(to 1730kg)
bigger Brembo cross-drilled discs
redesigned lighter wheels
supplemental valence ducts at each corner
F1 transmission option
4 mph faster top speed
new lighter steel bodypanels with larger front grille and brake ducting openings
new headlights with Xenon projector beams and body color coded surrounds
new instrument binnacle
new treatments to the dash, door panels, seats, transmission tunnel
optional 19" wheels
Nah, they were both bone stock (well, Paul's had the Tubi exhaust). If the 575M was any better, Paul would have been all over it, too. It never really made sense to me, the 575M. I think they should have kicked out a 575LM street car in limited quantities instead until they roll out the new flagship car in a couple years.
But, hands down, if I had the caysh, the 550/575M would be my daily driver. It's a beautifully subdued car, it's fast, handles well, and doesn't beat you up at all. Pretty much the perfect GT car.