I installed a PID on my Rancilio Silvia for about $50 : r/espresso
Rancilio Silvia versus Silvia : what does the meCoffee PID do? - YouTube
PID Control Retrofit KIT for Rancilio Silvia w/ screw RTD sensor PID Temperature Control Retrofit KIT for Rancilio Silvia Espresso machine [KIT-RSRTD] - $149.50 : Auber Instruments, Inc., Temperature control solutions for