if you are going with aftermarket rotors, go with slotted. Also stock sized rotors dont really do anything as far as braking. The pads are the key element in the braking effectiveness. The only thing slotted will do is reduce pad glazing, thats about it. For the longest time i kept stock rotors and just moved on to better pads instead of wasting money on fancy looking rotors.
Just my 2 cents
Member # 54233 and The 4th Z32 Project.....Its time to do it all over again...