There`s not enough room in the rear seat to seat your rear.

When you look behind before changing lanes, a blind spot obstructs what`s coming up from behind.

The head rests are so hard that each time you lie back you fall victim to what feels like a self-inflicted whack with a 2x4.

And there`s neither an air bag nor anti-lock brakes.

A very nice car, that 1992 Nissan 240SX.

Of course what makes it nice, or at least more than tolerable despite the annoyances and aggravations, is that this is the convertible version of the Japanese automaker`s compact sport coupe.

There`s a saying among collectors that when the top goes down, the value goes up-and so does the enjoyment. The ability to drop the top makes up for a variety of other 240SX shortcomings-at least in the summertime.

We test-drove the 1992 240SX that went on sale in May. It and the 300ZX represent the first new softtops from Nissan in more than 21 years.

Anyone considering a LeBaron convertible should check out the 240SX before signing on any bottom line. In craftsmanship alone there`s more attention to detail with the 240SX, not to mention such a snug fit that you don`t get any more wind noise than if you were in a hardtop coupe.

Bear running backs should move as fast as this top does. Unlatch the top at each side of the windshield, push the button marked ``top down,`` and by the time you finish a blink, the top is folded and resting in its stowage container waiting for you to slip on the tonneau cover.

The swiftness sure beats a manually operated top and is many times quicker than most power tops, but it does present one drawback. If you don`t keep your hands planted firmly at your side when the top is moving, you`ll spend the rest of your life limited to counting to the number 9.

The return to the closed position is equally fast.

Speaking of quick and fast, the 240SX`s 2.4-liter, 16-valve, 155-h.p. 4- cylinder engine is no slouch in responding to your command. Some will enjoy the engine growl when you kick the pedal, though others will wonder why the need for sound effects in a car meant more for laid-back cruising than off- the-light power.

Standard equipment includes power brakes and steering, power windows and door locks, AM/FM cassette with power antenna, cruise control, tilt steering, leather-wrapped wheel, and driver/passenger vanity mirrors. Air conditioning and a compact disc player are the only options.

Base price is $21,995.

Nissan says to keep the 240SX convertible a limited edition it will build 20,000 copies and then no more. Through Aug. 7, sales were at 10,521 or just past the half-way point.

>> 1992 240SX convertible
Wheelbase: 97.4 inches Length: 178 inches Engine: 2.4 liter, 155 h.p. 16 valve 4 cylinder. Transmission: 4-speed automatic. Fuel economy: 21 m.p.g. city/26 m.p.g highway. Base price: $21,995. Strong point: It`s a good looking convertible. Weak point: Basically only one strong point, plus no air bag, no antilock brakes, no room in back seat, blind spots. >>