hell no its not a fair price!, you can get the copper plugs for 2 bucks each and wires for under 40, 60 bucks tops for it all.
Tools: ratchet, 5/8 th's plug socket, and a 3 inch extension, and i think a 15mm for the dog bones.
if the wires worry you, pull one wire, remove that plug, replace that plug, then remove that wire and replace it, you cant mess a thing up doing that way.
it shouldn't take longer than 1 hr to do this, i did mine in less than 30 minutes my first time out.
look at like this 300 bucks in your pocket, not the dealers.....