The day before yesterday, I found a predictable fix for my other two cardboard wheels of the type I repurposed for the Ecto-1: sanding and filing them by fitting to the rotary tool, which I thought might be destructive for cardboard but did the job pretty well. Could be the glue that held the thin paper treads made the wheels strong enough to be sanded. Also took the opportunity to paint the sides to get the accurate white rims and silver hubcaps rather than plain silver. While not as smooth-rolling as the rubber-tyred plastic ones, they make it look much more complete and there's no need to remove them for other shells. Prior to that, the support beam was partially filed down since it was very low-riding and should've been 'on' the floor instead of under it.
Being upset with the inconsistent hand-drawn No Ghost signs, which were made of small, round office labels and never turned out right, I (somehow) found it easier to draw it on a regular sheet and then scan it twice before cutting out and gluing. It took several attempts until I got a result that looked good enough to copy and put on the model, because it's still hard to do with a pen at that scale. Mooglie still doesn't look petrified, and his nose turned out more like a Chaplin moustache. Both number plates were redone as well to make them brighter and more readable, still without room for "NEW YORK" at the bottom. Now that I think about it, I could also replace the painted louvres with zip ties to make them a bit more refined.