I'm using the same plug I use in all my engines including the .21 & .26 PICCOs and my TRAXXAS trucks its the Megatech Platinum Off-Road Glow Plug(under $4) I'm still on my 1st one since I got rid of the plug that came with the truck and it's working fine.
http://www.megatech.com/product_deta...s.php?ID=16192