http://www.dispersor.com/gta4 scroll down to vehicles

I should mention that the list isn't complete since it's missing the forklift which has by far the best acceleration of all vehicles. Top speed is shit though, so don't use it for races unless you want to meme the IL memes.

Also Super GT is missing, since this doc is focussing on classic% and the only way to get one is to lose 3+ min during the run. It's in the level of turismo-banshee in terms of speed.

Another good vehicle not mentioned is the futo. It has really high acceleration and maybe the best handling of all cars. Could be useful in races with a lot of turns.