Odd huh? I think the 04 seats look like shit. Opinions are like assholes I guess. I would have got an '04 for the lower production numbers too, but I bought my '03 new in back in Nov '02, so, yea... that wasn't really an option
I've never seen any place I can get the car weighed, so no it hasn't been weighed. The scales at both tracks look closed and completely abandoned every time I'm there. But, I know what it weighs stock, and I can do math, so I can tell you what it weighs now. I have the weights in a spreadsheet at home, with all the gains and all the losses. I'm down about 150 lbs IIRC. It was well over 200 lbs before the dynamat.
One more thing you can remove is the front sway bar, it's pretty heavy. I've had mine off for drag racing, but it's back on now.