The old decals were printed on clear decal film using an Alps printer. But they weren't the best quality because first of all, Alps halftoning is poor and second, they didn't use the finest halftone setting (or they didn't have the MD-5000 printer which is capable of the fine halftone). But they did have white underlay so they were opaque when applied to a darker color model.
I read somewhere that the new ones are printed using a color laser printer on white-film decal paper, then the image is trimmed on a laser cutter. I haven't seen those in-person, but just going by the description, they will be better quality than the old ones. If the laser printer is capable of using dot-scatter halftoning then the quality should be close to what is on the MTL graffiti cars.
