Actually they don't cool faster. AIr doesn';t move through the wholes except possibly when you are stopped. Maybe in the days of soild rotors, but with entilated rotors the air moves radially through the rotor and hole don'
t do anything, except start cracks.
And many race teams, as well as people who track rotors with holes in them, find them cracking between holes.
You under estimate the potential of a stock E46 M3. You are talking about a car that one street tires
is good for 145 at the Glen and 135 at VIR (two place on the full track), and over 140 at Summit Point, and weighs some 3400 pounds with people on board. Add in R-comp tires
and any form of suspension upgrade, and you are talking even higher speeds into braking zones. The car is bloddy FAST, and bloody HEAVY. LOTS of brake energy.
SS brakes lines don't do anything for dealing with heat. They do enhance pedal feel by eliminating one more area of flex in the system.