Based on temperature and wear I don'think vented rears will buy much. I work on a lot of race cars and vented rear brakes are uncommon until your either over 155mph or your car weighs over 3500 lbs.
Spec miata for example uses Hawk BLue pads front and Hawk Blacks in the rear because the blue don't get hot enough to work in the back.
Dave __________________
Dave - PDX
1995 318ti - Active Black and Tan.
2005 330xi - Mtech 1 - 6spd - Orient Blue/Black |