I need some advice on the next upgrade path on an mid 80's Linn Sondek. So far I have had a Rega RB251 arm fitted together with an OL counterweight. Possible upgrades I'm considering are the power supply to either a Valhalla or an Armegeddon clone, a complete rewire of the arm with Cardas wire and a new cartridge. Present cartridge is an Ortofon 2M Red. Which upgrade would bring about the biggest improvement in sound quality?