The company I work for has Ford Partner Program eligibility. Mazda doesn't use the exact same "X-Plan" as Ford, they call it the "S-Plan" at Mazda. But because Ford owns part of Mazda, if you have a Ford Partner Program Plan, it'll work at Mazda.
I got my Mazda 3 on the S-Plan.
I had one dealership tell me I was getting it, but quoted me a different price and then told me that "since it was in high demand, they had to up the price a bit." I said "No thanks."
I had one dealership flat out tell me that I couldn't have the Mazda 3 at the S-Plan because it was so new. I could have any other car on his lot of the S-Plan, just not the Mazda 3. I said "No thanks."
Third dealership said "Sure!" And right there on the actual car invoice was the S-Plan price right next to the E-Plan (which you can only get by working for Mazda I believe)... and that was the price I paid.
It completely varies from dealer to dealer. I would recommend calling the dealers first and ask if they offer the S-Plan on their Mazda 3s... if they say No... hang up and call the next one. Dont worry about features/colors... I got the dealer that was willing to work with me to switch out to another dealership for the color I wanted.