They dont weight that much anyway. Mine weighs in at 940kgs with a full tank of fuel and full interior With a 1600 in it. Only thing on it that I've saved weight on is the wheels at about 20kgs lighter Over the SR speedlines, 17kg per wheel with tyres vs 12kgs with some 4kg ish jap wheels. Rear bench doesnt weigh that much on it own but the seatbelts do So in total would be a fair saving All the hard Sound proofing stuff would add up if you got it all off. Then id start thinking about buying lighter panels but thats a last resort as you can do much more cheaper before hand. As above Aircon, and even swap your powersteering for an electric setup to take the drain off the engine.