Prusa i3 Hephestos (BQ)(GB)

I'm looking for this spare part in Europe, I've found in USA, but the shipping cost is more than changing part
https://www.dropbox.com/s/dh9zkqrne85503c/IMG-20160219-WA0019.jpeg?dl=0
Thanks

Is anybody having difficulties getting dimensions in the X Y plane to be accurate?

For example, a 3mm hole, being at least or close to a 3mm hole?

I seem to have issues where the lower layer dimensions, are smaller than the model dimensions, seems to cure itself as it raises in Z.