There's an expert 45 on the EE.....  does the 45 expert come with a mag well?

Any significant difference other than threaded muzzle and necessary raised sights?

The only differences are the obvious ones. I own the Expert.

Most Experts do not come with the Jet Funnel.  Since it is a .45 then I know it will not come with a JF.  FYI: If it were a 9mm or .40 and did come with the JF then you can only use the increased capacity white mags with it (18 in 9mm, 16 in .40).  There is no increased capacity mag or JF for the .45.
With the JF on the pistol normal cap mags and the neutered 10 round mags will not lock in because the white mag's body is about 1/2 inch longer.

The only difference between a Tac and Expert is the Expert has a longer slide and sight radius.  The Expert does have different sights on it but they are almost the same.  While the Tac has tall normal shaped sights the Expert has sights that are taller than normal but not as tall as the Tac and they are shaped like a hook.  Great for target work but lousy for carry or duty unless you change out the fish-hook front sight.  The Expert does not shoot any better than the Tac from benchrest but some can shoot better with the Expert because of the longer sight radius.