Got around to installing a Euro-style taillight on my '23 Special Edition. There's an inner rear fender that I was able to remove, so I didn't have to mess with the entire fender. The diameter of the US-spec taillight lens is 115mm, and only 65mm on the Euro one. It functions exactly like OEM, and the turn signal lenses are still the width of a license plate apart, so there shouldn't be any issues passing a state safety inspection (it DOES have a DOT stamp on it). Looks much better than the mini-headlight size OEM one...
Oh, and with the exception of the two allen head bolts on the side (green arrows), everything else was a torx-bit...