"Interior plastics" refers to the plastic components used inside a car or other objects, such as dashboard panels, door trims, or center console. Full definition
The bad: Cheap interior cloth on all seats, cheap interior plastic everywhere that scratches very easy. (cars.com)
I also continue to be disappointed by Mini build quality: it seemed like every piece of interior plastic on our JCW creaked and rattled loudly, even with just 2200 miles on the clock. (automobilemag.com)
Interior plastics look okay but they're all hard surfaces. (automobilemag.com)