It very expensive and not at all profitable.

Using OverdriveNTool v0.2.9, you can adjust the frequency and voltage of the core, maximum core temperature, and fan speed.

In addition, one of the most desired feature by miners is provided as well – adjustment of power consumption.

https://bittention.com/software/download-overdriventool-0-2-9-updated-to-the-latest-version/

Claymore Remote Manager is designed to support remote monitoring and management via JSON protocol over raw TCP / IP sockets. The program enables to get recent console text lines via HTTP.
The main feature of Claymore Remote Manager is monitoring and management. The program monitors hashrates, GPUs temperature, fan speeds, current pool names, etc.

https://bittention.com/software/claymore-remote-manager-download-windows-version-only/

Сorrect, just the shaders, no overclock or voltage changes. There's a new check box under additional features. Just check unlock 6970 shaders. Save bios and you're ready to flash. You can still overclock after unlocking the shaders.

https://bittention.com/software/radeon-bios-editor-rbe-v1-28-download/