Heat gun to warm up the glue... Floss to remove the badge... Then you can do several things to get the remainder of the glue off, but rubbing alcohol works best...Where did you buy the badge and how did you get the FX badge off?
I gotta ask--why would you do this? I get it that is essentially the same car.
Your rebadge is not to the same level but it somewhat reminds me of the Corvette I saw last week with Ferrari badges on the front panels and an old co-worker who rebadged his 5 series BMW with the M logo because he upgraded a few trim parts.