The Infernus actually has a faster acceleration and a better top speed than the Comet. I use to have a link which let you compare any GTAIV cars with others and the Infernus is overall the fastest car in the game. The Sultan RS has the best acceleration but has a considerably lower top speed than the other supercars, making the Infernus the best car to use in long, straight races. Of course, personal preference does come into account for a lot of people.