Brett, the cost was around $16usd I think for the rails and shipping was a bulk order with the shaker etc.
As far as if you need them or not, you can get away without them but I prefer them in.....also check beakys post above,maybe ask him how much easier he thought the game was to operate on with the rails installed. They should be standard issue imo.
As far as led ghosting goes...I have no idea.