This may be obvious, but I ordered a set of front and rear rotors from R1 concepts; how do I tell which are the front and which are the back? I know which rotors are pairs (because of the part numbers) but I don't know how to determine the front from the back.

Also, What direction should the rotors be pointed on the car?

Like this: http://www.bmw-sg.com/features/leuberz4-jan2006/le-uber-z4-4.JPG (what I would consider backwards)

Or the opposite way?

There is only one direction that the rotor will fit due to its cross section being the shape of a hat where the indentation fits over the wheel bearing. Also the rears on GTP's are smaller then the fronts. Fronts being 11 inch.

the slots should face the rear of the car, but it doesn't matter either way. One way will have more brake dust and more stopping power, the other will have a little less brake dust and a little less stopping power. Nothing dramatic though.

As for front and rear, you will be able to tell when you get them. The fronts are larger in diameter. I dk how to word this with proper terminology but the rear rotors 'hub', like where it attaches to your wheel hub, sticks out farther from the rotor than the front ones do.

yeah it will only fit one way, but if u take it to the other side of the car it still fits but the slots are facing the opposite direction. Thats why hes asking what way does it go.

you brakes will last longer and you will get less dust if you put the rotors spinning into the pads. Of course, more friction = more dust = more braking power but I don't think its worth the minor improvement for the reduction usable life.

Are you saying to put the rotors on the way they are in the picture I posted, or the opposite way?

Of course! however, are we talking huge percentages? if you are desiring to stop from 70 mph you'll do so in roughly 300 feet. Can anyone say what he difference in stopping distance actually is in an equivalent test (same speed, same conditions, same car)?