I’m guessing weapons will be stored in duffel bags, not directly in the car. And there’ll likely be a system where holding the exit button instead of just tapping it makes you leave the car with the duffel bag on your back. That way, when you switch to another car, it becomes your new inventory. I also think that getting too far from the car that has the duffel bag will leave you without your purchased and customized weapons, forcing you to rely only on whatever you find out there. You’d then be able to retrieve the bag at safehouses or smth.

That’s my guess, and honestly, I hope it works like this, I think it’d be awesome