After extracting the XY coordinates from geometry data via "save as csv" I get coordinates which are about 150 km more in the west than they should be. North/south seems right. I set the CRS to MGI/Austria M28.
Any suggestions?
The EPSG Registry also lists West/Central/East zones (they may be deprecated; I can't access the online registry right now at 8:54 PDT on 12 March 2013). Their false easting values are 0, so the West zone and M28 should differ by 150km in the easting coordinate values. Try using EPSG:31254 instead.
there are different EPSG codes for Gauss Krüger projections in austria. Here's a list of them http://wiki.alpine-geckos.at/wiki/SRID Maybe try the other ones.