I don't know what popular opinion might be but I for one understand the situation... It might be best to think about being specific:

Front passenger seat, seat belts and their attaching hardware and bracketry may be removed or substituted. Rear seat back, rear seat bottom cushion(s), sun visors, rear seat belts and their attaching hardware and bracketry may be removed.

...making distinct what can be substituted and what can only be taken out...?

K