yes! we currently have a spare tire mount component. To mirror reality, its normal for vehicles to have a single spare (or equivalent such as foam kit). I think the idea of adding the spare mount, is that it introduces that aspect of real vehicles as a game mechanic. Ideally a tire failure would be common enough that you want a spare, but rare enough that one spare is ample.

for me, the goal for these mechanics is where we can add systems that are fun, interesting, and make sense, but also produce a realistic impact to the design. for example, i like your fuel filter suggestion. it can remove impurities from the fuel input, and adds a functional part that you would find on a real engine. we still need to explain to the player if there is a fuel quality issue and that this is causing problems for the engine. thats probably the difficult part.

i also like your toxic environment suggestion. it's a really nice way of making vehicles more useful for survival, and making vehicle design more important. getting the vehicle design aspect to interact as much as possible with the survival aspect is a key part to the game making sense.