Believe it or not the back seat backs are decently heavy. At least 10-15 lbs each i would guess. Get rid of those, the shelf and spare tire and the rear interior and 50 sounds about right. I recomend doing it if you plan to race for a weekend or something. Its quite easy... unless you have a TRD
rear strut tower bar then its a bitch gettin the rear plastic side panels and tray on and off. But the seat backs come out super easy, 2 bolts each (either 10 or 12 mm socket, i forget) Only other problem about removing the interior is the driing noise gets much louder.