Now I got it
Did the change from the oem-rotor to a rotor with grooves increase the braking performance? Or is it more an optical effect? And how long are you driving with this brake-setup? I would like to know how much it wears down (had performance-brakes on my motorbike; performance was awesome, but the pads and rotors didn't last very long).
On the other hand, I don't think it would be street-legal (at least in Germany) to mount a rotor from a VW to a Daihatsu with an adaptor, because it is not approved. In case of an accident, if the insurance company finds out about this modification, I don't think I would be happy...
But I'm still very interested about the Green Stuff pads.