happen to be in a HSP/Redcat vehicle? that would be right then as being a VX. pretty sure those are standard with a hot glow plug, try to get some 20% fuel for that engine. if that plug fails, get an OS of similar qualities, do make sure though to match the plug type to the engine. (i.i plug...
agreed if it is cheaper to buy per gallon go that route, but around where I'm at, my LHS has to pay hazmat fees for deliveries on gallons, but not quarts, so fuel is over 60$ a gallon, but a quart is 10-12$.
as far as which glow plug per fuel to get, lower percentage nitro (under 25%) it doesn't...