The difference between the z and the sx is that the sx is pretty much for drifting... the s13 is one of the most dominant cars built when it comes to drifting.. Although I don't autox or road race, i would think that you drift? If so the sx would probably woop on the z. With that in mind the z would PROBABLY don't quote me on this, beat the sx in the straight line.. due to the fact that the sx wasn't built for dragging, it was built for going around corners sideways.. anyway... just offering my .02