"Aftermarket" is a term used to describe parts that are not made by the factory. So for example, for your Ferrari F430, if you buy parts for your car that are not actually made by Ferrari, then those are termed "aftermarket". Many people use the term "F430 aftermarket parts" specifically when referring to custom parts for the F430, like performance parts or custom appearance parts. But even if you just replace your F430 brake pads with OEM-grade factory-style brake pads that are not made by Ferrari, those too are aftermarket F430 parts. Over the course of a vehicle's life, it almost certainly will have aftermarket parts installed in it at some point, even if the vehicle is never actually "modded out".