I wrote about the only part the people have to care about here:
If you need more WAN->LAN speed use flow offloading: How can flow-offloading be enabled on lantiq xrx200 devices?
And you probably also want to update to the latest DSL-Firmware that supports VDSL-Vectoring and runs in general better then the older preincluded version: Howto: Updating the Lantiq XRX200 devices with latest DSL vectoring firmware