Eh, just have a cut scene with the Ecto-1 driving to the next mission. When the mission starts, have the car behind you. That'll do for me!
Maybe even have the car “break down” when you are going on a chase at the start of a mission, therefore you have to go at it on foot! lol. That'd make a great on-foot chase sequence.
So I guess you've tried simple “electricity” option? Wouldn't they give some sort of option of having that as a gun? Or a grabbing ray? Hopefully they can do add-ons and someone has created something along those lines.
I don't want to be using “Spectre-Snares” :p (God how sad, I can actually remember the gun from the “other” Ghostbusters LOL)