I know it sounds strange but I have this Aston Martin DB9 weighing at 1740kg and I want to use it at the heavyweight open event in the proving grounds section. The requirement is 1746kg. I already installed all of the weight increasing upgrades.

put ur mom in the trunk
OH DAMN DUDE

haha! nah, she won't fit, your sister is taking up all the space

Isn't it a bit silly to say, you've added all the weight options? If you have added everything I very much doubt there is anything you could do to get it even heavier.

Try putting different rims on it.

there are no "weight increase upgrades.... :S"

Also, add rims, spoilers/bumpers, and i'm not sure hwether engine/drivetrain upgrades increase weight, but look into it.

Taller rims and tires WILL add weight as will spoilers and air dams if they don't replace stock.  Some motor changeouts will add weight as well.  Easiest would be to roll w/some 20s,lol.

Just buy a dodge charger, they're massive, look sweet, and are pretty fast fully upgraded, but handles like a bus