The problem with changing region on a PC Drive is that it has the 5 times limitation. If it is a DVD with region protection, merely use DVD Decrypter and ImgBurn to create a region-free DVD. If it is a dual layer disk and you have to reduce the size to make it fit onto a single layer DVD, use DVD Shrink.
If your DVD from Germany is merely PC Data, you will be able to read it on any PC with a DVD drive.
Finally, the cheapest DVD drives for playing movies are usually not region protected - I sacked my $350 Sony for a $39 Walmart special - it plays everything, including VCDs and MP3 disks.