Cool! I didn't know you were talking about a Rockford Fosgate edition.
We looked into this a couple months ago here in another thread. Here is a link to that thread: Rockford Fosgate Edition Mirage (U.S.)
Mitsubishi started with a DE model, put some ES gear on, included some Rockford Fosgate equipment and badging, and called it the Rockford Fosgate edition giving Mitsubishi one more trim level to their lineup: DE, RF, & ES.
Here is a snippet from the Mitsubishi press release: Mitsubishi Motors Announces 2015 Mirage Rockford Fosgate EditionNot sure why Mitsubishi did not include pushbutton start and FAST key with this, except to perhaps keep costs down? Other items left off include fog lamps, leather shift knob (all RFs got a CVT), driver's seat height adjustment, and side mirror turn signals.The Rockford Fosgate Edition starts with the Mirage DE and adds a 300-Watt, Rockford Fosgate ecoPUNCH™ sound system, steering audio control, Bluetooth® hands free phone system and audio, cruise control, leather wrapped steering wheel, alloy wheels and special badging.
More details on trim levels, pricing, and port options can be found at Mitsubishi's website: 2015 Mirage Pricing.
As you can see, all ESes (and only the ESes) got the pushbutton start and FAST key. I got one, and though it was not an option I had sought out, I like it's convenience. The more I learn how to work with this FAST key, the more I like it. The only problem I have is the FAST keys are crazy expensive. That is what caught my interest in your one post - a cheap replacement FAST key. If you ever find one, please share it here.
That's a pretty rare model Mirage! It would be good to get some detailed photos posted of the car's exterior and interior. Other RF members have shared info about the Rockford Fosgate equipment installed. Good to know there are others here too!
Thanks.