vdsl2 50 down 10 up, about 43 down and 8 up after taking out overhead.

Speedport W 920 V <- get this one, it's about four euros a month to rent.

Windows XP:

1) http://www.rainerullrich.de/ruKernelTool/ruKernelTool-von-65.04.78-auf-75.04.76.html
Instructions on how to switch the Speedport W 920 V firmware over to an AVM Fritzbox 7570 German, French or English (!) firmware with multi-annex support (no need to concern over annex A (most of the world) or B (germany).
Print out or get the PDF.

2) Get the ruKernelTool http://www.rainerullrich.de/ruKernelTool.html beta. I used 4.4.4 for this, released september 17 A.D.
2a) There is a password and username for the download. If you use Google Translate or your german is decent, you'll figure it out. It's on the page.

3) A laptop with a working wireless internet connection. Hook up the ethernet port to the LANx port on the Speedport.
3a) Make sure there are no unsigned third-party network drivers loaded like 'CFOS Speed' or 'PPP over Ethernet (RASPPPOE)'. These are drivers listed on the ethernet network connection properties, causing a warning box about 'unsigned' when reconfiguring the network cards. They can be un-installed for now. If you don't know what (3a) is, then you can probably ignore this warning and continue.

4) Run the ruKernelTool as Administrator. It must reconfigure the network connection so it should have administrative access to the laptop.
4a) Follow the instructions as listed in (1). If you get an error 63 or 64 when going through the 'Info-loading' phase (Adam2) and it looks like it's trying to assign a network address of 99.88.77.66 to the laptop ethernet port, then see (3a). ruKernelTool attempted to change the ethernet settings but ran into a snag caused by third-party drivers.

5) the instructions in (1) vary a tiny bit as the ruKernelTool has been upgraded since the instructions were created. It's not substantial, just keep plugging away, you'll get it.

Google translate fails to translate the instructions correctly about when to unplug the Speedport, inverting what is an instruction to make sure the speedport is powered off, into the opposite. You'll catch it if you just take a little extra care.

Reconfigure IP address -> unplug speedport -> press Continue on ruKernelTool when ready -> ruKernelTool waits 30 seconds for Speedport to be plugged in.
It's while the speedport is starting up that ruKernelTool has access for a few seconds to the kernel to flash the fritzbox software over.

When you are done you will have instead of a speedport W 920 V in german-eese, a friendly fritzbox 7570 in english.