Thanks guys for all that infos and the link to the penguin repro shells!
Great, as i do need another body and undertray for my yz-10 as well, so i can do a combinated order than!
Gainsy: i'll look what i get and let you know, if i can spare the aloy z bracket, or any other part.
MattW: if you have a striped thread in your z bracket and there is enought material, you could use a thread insert, like in the picture.
I use some of this with good success.
For example, for a new M3 thread you have to put a M5 thread in the material and than screw the insert with some threadlock in it and you have a perfect new M3 thread!