How much weight gain from adding a Dana and roll cage.

I'm pretty sure my car is going to be a 4000 pound dart, judging by the weights of other people's cars lol

Mine I took a picture of on the scale after making a pass and posted it on here. Not all that long ago( this past summer). And anybody who has seen it knows it has no glass and no stripped down interior. And knows the size of me ..lol
I am a hater of people who say there car is heavier to make it sound faster.