The tune up is easy.
I just did mine the last couple days using various blogs. I am totally not mechanically inclined, so I'm sure you could do it. I would say its a fair price if you don't want to do it yourself. The tune up mostly should just be cleaning it well, fresh oil and grease, and a check over of the bobbin shuttle and tension assembly. I can't imagine what else could be done to it honestly. The tension assembly was the tricky part for me, but I used the pics in the manual and a good blog tutorial for it.
The wiring I can tell you tomorrow. My replacements are coming from sew classic tomorrow. It looks pretty easy, she has good instructions. The wall plug and plug into the machines are already attached.
Either way, if you aren't inclined to do it yourself her prices sound fair enough I suppose.