I used an LM1732 I believe? It's a 1A adjustable regulator 3 pin.
you can get them at radioshack while they still open.
you control the output voltage via the resistor combo or you can replace one resistor with a 5k potentiometer to make it adjustable. Best to have a tiny lcd voltmeter attached.
An HPI putz out 60w and I need to heatsink the regulator. I'm trying it with a 5A version soon