I think I'm going to approach this sketchy vehicle idling outside my house and say get the fuck out. Think that's risky?
Why would you assume the worst about the vehicle?
I don't want another shooting incident to take place
Rather than assuming the worst and putting yourself in danger, you should call the police to investigate the matter. It could turn out you're just paranoid and the person has legitimate business there.
People shouldn't just sit in their car outside my house. I have enough problems as it is.
They're not bothering you, but if you must interfere, don't put yourself in harms way.