If you want to know your car specifically, try this. If you live around farmland go to the nearest grain elevators...FS or whatever and they have a roll on scale for the grain trucks. When they aren't busy most will let you roll on and weigh. Or you could go to a truck stop. Most have scales and they cost under $10.
That way you'll know your cars weight with or without you in it and all the fluids and whatever else is in it like a sub box.