I have an extremely rare version of Superman III on DVD (transferred from a VHS recording taken from TV sometime around the late 1980s) featuring the extended edition of Superman III, which was only ever shown on TV. It is pan and scan, so not the correct aspect ratio, but everything else about it is superior as the extra material improves the film (it's still not great, but I definitely prefer this version). It even has an alternative opening credits sequence in space, much more akin to the first film, instead of the horrid credits over the opening slapstick sequence, which mean you can't see the action properly (it looks like someone smeared vasoline on the lens).