The requirements to face JV are:
(7) Race Wins
(5) Milestone Events
(4,050,000) Bounty
Races:
Speedtrap Race
Drag Race
Speedtrap Race
Vega is one of, if not the hardest blacklist member. I had the most trouble with him. I missed out on winning his pinkslip, and couldn't be bothered to go through the three races all over again. But it should be the first marker. (The one I didn't take.)
I used Ming's Lamborghini. Before you challenge him, I suggest paying for the stage 2 NOS. Might make it more easier for you than it was for me.