Putting a convertible top on a car doesn`t guarantee instant success.

The Infiniti M30 convertible from Nissan for 1991 is a prime example.

The compact Infiniti G20 sedan is a neat machine. The large Infiniti Q45sedan excels in the performance department. Yet the M30 coupe is a misfitregardless of what top it offers.

We test-drove the M30 convertible and found the aggravations made itdifficult to appreciate the good features, such as the 162-horsepower, 3-liter V-6 teamed with four-speed automatic. That engine claims 0 to 60m.p.h. in less than 10 seconds, yet is rated at 19 m.p.g. city/25 highway.

Antilock brakes are standard as is a driver`s-side air bag. In additionto the open-air freedom of top-down driving, you`ll find a host of standardpower goodies.

But annoyances detract from driving pleasure, one being that the driver`s seat doesn`t go back far enough, meaning your body is too close to the wheel and your legs are too close to the pedals.

If you get in and close the door before reaching back for the lap/shoulder belt, it`s almost impossible to reach back and find the metal clipand pull it over your torso into position. The driver`s seat is too flush tothe driver`s door and stands as a barricade to slipping the belt over yourtorso.

The EPA rating was impressive, though maybe imaginitive would be a better word. To say the 3-liter guzzled fuel would be an understatement. It was as ifthe fuel tank was tied to an intravenous cord leading directly to the Mideast.This was one thirsty machine.

The M30 starts at $31,000. The Olds Cutlass Supreme convertible we tested a while back (Cartalk/Aug. 4) started at $20,995 and loaded with optionslisted for under $24,000. It lacked an air bag but had antilock brakes andoffered a peppier yet quieter ride, with far less wind noise, roomier frontseating with proper positioning from the wheel and pedals, a back seat thatfits two adults and better overall looks.

Until Infiniti drops the warmed-over Leopard and comes up with a viablealternative, save your money and get the Cutlass Supreme convertible.