I don't think the Basic Standard Poverty Spec items should be in the main categories, but optional extras are OK imo.
E.G: Xenons, Cruise Control etc. OK,
but stuff like GTI seats, GTI dials, GTI bumper, kick plates etc. should be in a sub category "Standard GTI Parts" because they are useful for those who don't have a GTI; Part numbers etc. but won't clutter the main listings for those who have them already i.e. Every GTI5 owner.