Most new vehicles are a far cry from those old dirtbikes, mechanically and electronically. For automobiles, crash safety standards and market demands have meant ever-increasing weight. Power has had to keep pace, so the complexities of impact structures and crush zones have been joined by those of four-valve cylinder heads and variable valve timing. Emissions can't increase as the power increases, so there are the additional intricacies of direct injection and other "clean" tech. It's a vicious circle, with new regulations and new market strategies requiring complex new technologies.