Hi grey! Welcome to our forum!
I've got a Materia 1,3 but actually didn't face brake problems because it only ran 14.000km since I bought it. But also I'm searching for special brake pads, but didn't find any for the Materia yet
. But I guess that the brakes of the Toyota bB should be the same as in the Materia, and I found EBC Green Stuff pads for the bB on eBay.
Maybe I didn't quite get it, but where did you get the brake discs withe the spiral grooves from? From a VW Golf???? If so, what did you modify to get them fitted??
Greetings