Just scaled down a bit.
The rear 'windows' on the MX5 ND (which aren't actually windows at all, they are purely decorative black panels) are the same shape as those on the 240Z.
The ND's front grille is also surprisingly large - the same as 240Z's front grille (noticeable if you remove the front bumper).
A coincidence? I think not.
The big difference is that the 240Z had a huge boot, the ND boot is a bit of a joke.