Please help!!

I have a issue with the driver-side power seat.

About 2 weeks ago the motor started making a weird noise. It would sound like it is struggling as if something is caught in the rails. It starting getting progressively worse and only one side of the seat starting moving as if it was off the rails. Eventually it stopped moving altogether, unfortunately the seat is too far front for me to get in, I had to get it towed to the dealer. It is my understanding that this a common issue, especially for SUV models

This is a Certified Pre Owned Vehicle, should it cover this issue? Dealer is going to check for me, but I like to know if people have tried to get it fixed under warranty. Dealer says that rails and motor need replacement.
If not i'm royally screwed. Orange Coast Infiniti wants $2,400 for parts and labor (insane for a non-power-train issue).

If it is not covered I am definitely going to try and fix myself. has anyone tried to do this? how easy/hard is it to do? what parts do I need to purchase? I'm thinking entire seat rail system and motor, anything else I should know about?