I imagine the answer depends on the specific market in question. Shoes, for example -- it would be ridiculous for a shoe-selling website to have a different page for each different size of the same model/color, right? It'd be impossible to navigate.
But the headlights industry might have some fundamental differences that require a different page for different sizes of headlights. 2 criteria to consider:
Does each product include a large amount of sizes, like shoes, or few sizes, like under 5? The fewer sizes, the more feasible it is to have a separate page for each.
Are the customers going to be searching by size? (seems likely with this particular type of product) If so, it may be beneficial to have a separate page for each, but there may be other, more sightly solutions.