The following list is directly from an owner in Australia.
* light battery (Oydessy 25 gives 23ah - and 280A cranking and needs a trickle charger when stored for over a week) (7kg)
* removal of heater and fan (3.5kg)
* stripping out of doors - no locks or winder mechanismisim, plastic glass, lighter hinge and no crash sidebar (26kg)
* Mog driver seat and removal of passenger seat (14.5kg)
* race without rear glass or roll hoop cover (5kg)
* light steering wheel (1kg)
* remove stereo and speakers (4kg)
* light fuel tank (6kg if you use Geary's 36L standard sized tank or 8.5kg if you use the 27L 340R tank)
* Japanese 44A alternator (2kg)
* removal tyre inflator tube (0.3kg)
* boot bag, boot cover and boot heat insulation (assuming you have an early car with the boot bag fitted) (4kg)
* remove the leather sill panels and have them fix on with velcro tape(1kg)
* remove reversing lamp and their grilles and the GRP (and leave them off if you can get away with it, or make them screw in differently soyou can remove the lights for each event) (1kg)
* remove ali passanger foot rest (0.5kg)
* remove handbrake and gear stick plastic covers (0.3kg)
* remove aluminum foot well divider - I don't since I can't get on without the footrest! (800g)
* use 340R aluminum wheels - these are rare and were made before the 340R mag wheels were sorted and a few sets are around (5-9kg depending on what wheels you have) or 340R mags that give another 8kg over the ali ones!
* remove washer bottle (0.5kg)
* use MMC discs for sprinting/hillclimbing, they won't have a chance to overheat (10kg)
* Hispec racing rear calipers (5kg)
* remove alarm siren (if you have insurance that only requires an immobiliser) (0.4kg)
* mud flaps (0.5kg)
* early rear wheel arch liners (2.8kg)
* removal of a-frame/petty-bar replaced with welded in diagonal brace bar and, replacing rear roll hoop stays with larger diameter tubing (7kg)
* carbon under tray diffuser (1.5kg)
* no rear silencer (just using the same tuned length of pipe work after the silenced cat pipe - will be ok for competition noise) (3kg)
* replacement radiator (1kg)
* front carbon calm (wet lay) (4kg)
* rear carbon clam (wet lay) (8kg)
* carbon bonnet (1kg)
* carbon boot lid (2kg)
* carbon hardtop and coupe panel weigh the same as an ali boot lid and give much better drag and a roof for free, and don't require the roll hoop cover.
* carbon "race" wing and mounts instead of sport 160 "wing" (2kg)