Speedo, the Keyence requires no external diode or capacitor. You might be able to install a cap but the menual says an external diode will damage the unit. The esc is extremely user adjustable(more adjustments than a pitwizard) plus it has 3 programmed profiles. The unit also comes with an optional anodized heatsink for hot weather racing. I bought one in Dec. 2003 for the first time and after racing Novaks all this time I like it. I dropped the Drive Freq. to .6KHz from 1.5KHz last race and the car had serious punch out the corners. Also after a pro-stock race on a tight technical carpet track the temp of the FET's never got above 104F.