Residential DSL provider is terrible (CenturyLink). Need a modem that has strong diagnostics/metrics, thinking of Cisco ISR with VDSL WIC?

Hey folks, my ISP is terrible and I'm tired of not having good data on the quality of the line and DSL physical layer to use for troubleshooting/evidence that they need to fix things. Wondering if there are any modems out there that have really good diagnostics/line quality/monitoring capability. Presently i'm thinking either a Cisco router with a DSL WIC or some kind of DSL modem with an open source firmware that is able to do same.

Any recommendations?