You will need level 17 for this one. Its pretty straight forward and not unlike the other fast money approaches.
Access the Turbo Challenge in the extreme series and enter a decent car. The video below shows a worked GTR which if your at level 17 already, shouldn’t be an issue to get and modify. A decent driver could manage a lap in the low 1 minute somewhere. Its a 3 lap race which nets you 36k. So effectively by doing 3 turbo races in about 10 or so minutes you could have another 100k to spend on your next car. Not a bad way to vary the way you have money.
Check the video out below: