fet wire/ servo

[piggy]

hi there i have a schu mission with a budget servo,

but i have just bought a buggy with a ko propo servo with a blue wire coming out of it, going to the speedo,

is it correct that this blue wire is called a fet,

i cant beleive how quick the steering is, is this because of the fet?
now the ko propo servo has snaped a lug so i need to replace it, what sort of servo should i look at replacing it with,

i was also thinking about putting one in my touring car as well.

cheers stu