I was up at Espresso Parts Northwest the other day talking with Terry et al.
Saw the info on their La Marzocco PID upgrade kit.
If you have a Linea or FB70 you need to call them up. This is the real deal. Full retrofit kit. Relay, probe setup and PID controller.
And the price I saw.... a total, complete steal!
Before he sells out.
Oh... and if you have not picked up a Scace Thermofilter - you might want to snag one of them. The retrofit kit plus the Thermofilter and a Fluke and you'll have every espresso geek's dream rig.