Nature abhors a vacuum. that's what the 1993 demise of the NX sport coupes created in Nissan's lineup vacancy that was only partially filled by the Sentra SE-R coupe. And that, too, has disappeared. When the new, redesigned 1995 Sentra lineup was announced in late 1994, there was no longer a coupe version. But not for long. In place of the defunct Sentra coupe is a new family of Nissan coupes, separated in name from the new Sentra sedans, though they're the same size and share most of the same mechanical components. A spunky competitor of the Honda Civic, Plymouth Neon and Saturn coupes, the Nissan 200SX is a smooth addition to the reasonably priced fun-car market and may even replace the pricier 240SX before long. There are three different models: the base level 200SX, the well-equipped 200SX SE and the sporty 200SX SE-R. The base 200SX is a no-frills car with 13-in. wheels; the 200SX SE is the mid-grade model with 14-in. alloy wheels; and the 200SX SE-R is racier, with handsome 15-in. aluminum wheels and a little wing on the back. The latter was our test model, which was priced just over $15,500 complete with a peppy 2.0-liter engine, anti-lock brakes (ABS), air conditioning and cruise control.