I have recently fitted braking wave discs to my sp1 the fronts seemed marginally heavier (1 mm thicker) but the rear was much lighter while trying out my handy work they seemed to lose that instant bite although using the original pads. otherwise they have great feel and as for bling factor of the scale man!
personally oem rotors are just as good
sure i will find out come summer for sure
originals are for sale on ebay unfortunately im in the uk.