In The Sailormoon Second Artbook, Naoko said that she wanted to have Mamoru drive the Porsche 962 LM, a sleek, low model which she drew in the picture to your left. Unfortunately, identifying Mamoru's car in the anime is not so easy.
The first thing I looked at was Mamoru's car keys. I did this because often the emblem of the car manufacturer appears on the key itself, for example Volkswagen keys usually have a circle with the letters "VW" in the middle of it. Unfortunately, Mamoru's is very generic. I can not personally identify the V-shaped hole in the middle with any car company in particular. So let's look at the car's body style to compare it to similar vehicles.
Narrowing Down The Suspects
The next shot to examine is a full side-shot of the car. Unfortunately I couldn't get a decent shot where characters were not standing in front of it, so this will have to do. As you can see, it is a sporty red coupe. It has a spoiler which is slightly raised but not too high. The rear end of the car is very vertical. This shot of the way the rear is shaped ruled out my first guess that this was a Porsche 911. The 911's rear slopes down, while this does not. Like most two-door coupes, the two back side windows are very small, but not all small windows are shaped the same. This also helped me narrow down my search. My second guess was the 1991 Toyota Supra, obviously not an exotic sports car, but it did have many similarities. However, the hood, grill and headlights are absolutely nothing like Mamoru's car.
The 1990 Alfa Romeo SZ
I was looking at mostly exotic and expensive cars when trying to figure out what Mamoru's car was supposed to be. I did this based on several reasons. First of all, it is said that Mamoru's parents were well-off and therefore left him a lot of money when they died. That would explain his very nice apartment and two vehicles, while he is a 19 year old boy who rarely works a regular job. In the manga, Naoko wanted his car to be a Porsche, so I just put these two thoughts together and assumed that Mamoru's anime car would also be fancy and expensive.
The end result of my research came up with the 1990 Zagato/Alfa Romeo SZ. It is remarkably similar to Mamoru's car and I am convinced that this is the automobile it's supposed to be. If you are American and not a car enthusiast, then you may not recognize this vehicle because it is not street legal in the United States.
1990 Alfa Romeo SZ Compared
Physically, this car is shaped just like Mamoru's. It has the same sporty, "squatty" look to it. It has the flat rear end and the small spoiler. The hood and grill are what really convinced me, I must say. It has the same kind of intake on the hood. It also has the same peculiar upside-down triangle shaped hole in the middle of the front. The headlights are exactly the same, as are the blinkers. Overall this was the only overall dead-on car that could really compare.
Zagato and Alfa Romeo are two Italian car companies that make sports cars. These two car companies actually came together to create the SZ, therefore it is a compilation of both. However, it is still mostly known as being Alfa Romeo and not Zagato.
Its original base price was approximately $65,000, meeting my assumption that Mamoru would drive a rather expensive car. It has a 5-speed manual, rear-wheel drive transmission, and its V6 engine is powered with 210 horsepower. Not the fastest or the top of the tops, but still nothing to spit at. It goes from 0-60mph in 7 seconds. Its top speed is 155mph. This car was nicknamed "The Monster" by the press when it was first released. In 1992 after production of the SZ had ceased, the LZ was released, which was a roadster/convertible version.