intim3,
I've had 4 different sets of aftermarket taillights on my PT and NONE of them fit like the original ones did.
On two of them I took the "brackets" and bent them as close as possible to the body of the light so they would hold a little tighter than when they came out of the box.
On two others (see pic below) I put a small chrome strip (the kind that goes on door edges) around the whole light to take up the gap and it helped the "brackets" hold the light tighter plus it stopped the light from sliding around in the recess.
