Its not what you can remove and still drive the car... as in theory everything can come out apart from drivers seat, steering wheel, clocks and gearstick... its what you can remove that wont be a complete pain in the ass, and take ages to put back in. With stripping you get to a point where you're saving less and less weight each time you take another bit out. Go for passenger seat, rear seats all unused seat belts and rear plastic/ speakers (leave front door cards in) also spare wheel/ jack/ boot floor and parcel shelf etc etc. No point doing headlining, as you wont get it back up. Carpet should come in two bits, front and rear sections. Will have sound deadening under it too, this all weighs a fair chunk. Will need both seats out and a bit of patience to get it in and out neatly... up to you if you want to go that far. Leave the headrests, lol at that suggestion, they dont weigh much and do more good protecting your head. Im guessing you dont want to spend any money on making the car lighter, just remove bits you already have? Pm me if need be.