I don't know about the wires & plugs, on a Zetec all it
takes is 15 minutes and a $14.99 Wal-mart toolset.
The fuel filter is fairly easy on Contours (requires
crawling under the car though). Do a search on the
forums, there are several tricks posted how to avoid excess
fuel spillage (or choose to go your own way and smell of
gas for days

).
All you need is a flat screwdriver and maybe some WD40 to
undo the clamp bolt.
Tiv