The difference between invoice and MSRP is only about $700 on the FiST. This gives very little negotiating room. My Z-plan was only slightly less than $1500 off MSRP, so X-plan will be less. I have a copy of the invoice with my paperwork, but when they copied it, it cut off the A,X, and Z plan prices off the bottom.
In comparison, my Z-plan was almost $5000 off on my Explorer, but the MSRP was almost double the FiST on the Explorer. They just don't make any money on the FiST (or the regular Fiesta for that matter).