Great find!! Trans purple is probably one of my top 5 favorite finishes.
As far as replacing the trem arm, I've heard of replacing the entire collar section with a screw in collar. Search eBay for a Fender Floyd Rose trem arm. I have heard that there are mixed results. the size may not be right for that particular type of FR.
I will say that with the MM case, you really don't need to take off the trem arm at all. The interior has a cut out for the trem arm, so the case top won't push down on the trem.
You dont need to bother touching the trem arm.
Leave it alone it fits perfectly in the case without needing removal.
You also need to stop comparing it to the Gibson and the Jackson... its not fair as the Axis is in a totally different league and it will just depress you're other guitars. Last thing you want is a suicidal Les Paul.