The essence is superb balance due to near-equal weight distribution.  Part of this was achieved due to its rear drive configuration.  A rear-drive car is intrinsically more expensive to manufacture but is less bound to be front-heavy like a FWD car.  The 240SX was the only rear-drive car in its class. 

The investment in balance paid off this way:  It is still coveted by speed enthusiasts over a decade after production ended.