In GTA 4, there's a Lamborghini-like car called the Infernus, which is modeled after the Murcielago. Although, the Infernus is pretty hard to find and rarely appears in the game. To get one, you'll have to complete Bernie's storyline and missions in the game. In one mission, he'll gift an Infernus to you once you complete it. Another way to get one is by completing races hosted by Bernie in the game. In these side-missions, it's possible to win an Infernus if you win, as Bernie will gift you another Infernus. You might also be able to find an Infernus near the home where Dimitri's and Faustin's missions can be found. Typically, it would spawn on the right-hand side of the house. Being GTA, driving an Infernus should start spawning numerous examples on the road.