After careful selection, I finally found a decent model on Sketchfab. However, its production standards were highly irregular, with parts and UVs scattered chaotically. I had to consolidate them from over 40 materials and rework the UVs and textures.
For rigging, I used modular rigging components shared by @postprocessed on YouTube. Although the lack of customization caused considerable trouble when animating the car door and steering wheel, the vehicle chassis physics it provided were quite helpful.