groundsmanracing

Hi I'm new in owning a lupo and have one with from what i can see is with the usual gearbox fault of noise when driving. I didn't pay a lot for it as only a 2002 1.0 but would like to know what the gearbox codes mean eg mine has FFE but i have seen esy and others so wish to know what the differences are and which ones might fit mine. and is it worth rebuilding it myself. thanks for any help that might available.