I was able to get the Infernus by doing Brucie's races.....I was racing against the infernus's, Banshee's, Super GT's and Comet's.
They were being driven around me when i was making my way to the race.....so i jacked a few...put them in my parking spot and turned up to the race with a Infernus lol.....Try it out.....I had a field day!
Great tip!!!! Thanks