Murphy's Law of Automotive Journalism: Whenever a comparison test is scheduled - any comparison test, even if it was set up months in advance - all carefully laid plans will fall apart at the last minute. Take, for example, this comparison of four high-performance dream machines. To the casual observer, the scheduling of a product review is transparent. We automotive scribes simply obtain the vehicles from the Car Fairy, drive them, and write about them. Nothing could be simpler.

Except it's never quite that easy. In this case, the scheduling started two months before we wanted to conduct the test. Each manufacturer had to be contacted individually so we could reserve the cars for the necessary time, and the individual scheduling of course needed to coincide with the availability of each of the other cars in the comparison. As a final headache to consider: The more popular the car with other automotive journalists, the more difficult it becomes to reserve test time.

Since we were not interested in conducting a Civic vs. Cavalier vs. Neon vs. Golf comparison, we expected the scheduling to be tricky. Fortunately, we were able to secure tentative reservations for our desired sports cars right away. It was the confirmation of those requests that presented problems.

To make a long story short, the Porsche was canceled at the last minute because Playboy needed to take pictures of it (Playboy sells more magazines than anyone else in the world, so they get top priority when it comes to test cars). Next, the Viper we were supposed to drive was involved in a wreck and was totaled the night before we were to pick it up. Then, naturally, the NSX had wheel bearing problems and needed to visit the shop. And the Corvette? Typically, it was in perfect working order and was delivered on time.

When Murphy's Law strikes, the only recourse is to strike back by cursing the world, cruel fate, Mother Nature and Hugh Hefner. The next thing to do is to devise a Plan B. We had to compare something to the Corvette. Miraculously, a little luck somehow drifted our way at the eleventh hour and Acura called, saying that another NSX had become available for the test. Two down, two to go.

When you're stranded out of town without a car, what do you do? You rent one. We tried Budget Rental Cars of Beverly Hills (1-800-729-7350 ext. 136), just to see what it would cost to run the comparison test on our own. The folks at Budget turned out to be our guardian angels. "Edmund'sB.? You need a Viper and 911? You got 'em." Edmund'sB. Law: When at first you don't succeed, beg.

Perhaps the most telling sign of how difficult it would be to rate these cars occurred at Budget's office. The angel behind the desk looked up at fellow editor Karl Brauer and myself and asked, "Which of you wants the Viper and which of you wants the Porsche?"

There was a long pause as Karl and I tried to comprehend the question and wondered if it was some sort of trick. "Uhhh," we managed to grunt in unison. We hadn't expected to have to make such a difficult decision so early on in the test. Finally Karl muttered, "I'll...take the...Viper."