You only have to extend one wire for the wire tuck and that is the one going into the fuse box...I tucked my whole fuse box along with everything else on that side of my EF and I only extended the power wire going to the fuse box from my battery...took about 1.5 hours to do but it looks clean as hell. I also routed my fuel injector wiring under the intake manifold which made it look a little nicer too.