after reading your part 2 mods.. i guess i am gonna be a stage #1 dummy forever. :)
not everyone wants to lighten their car to the extend of installing CF parts and removing their rear seats... a good advice for weekend racers but not so practical for a daily home to workplace car. especially my wife. she will kill me if I removed the rear seats..
I guess by not having "tons" of rubbish or unused stuffs in the glovebox and trunk is good enough to save some weight. (believe me.. at times you can store up to 4kg of un-used stuff just in your glove compartment) hint: magazines and books are not light.. even some gardenia bread can be found under your passenger seat.. thats already some 10-30grams of added weight. :/ old newspapers, paperclips, durians, coconut the list goes on. Spend some time to clear all the unused stuffs.. you'd be suprised how much weight savings you'd get.
Another thing to improve acceleration & braking would be having the correct/optimum tyre pressure. So.. check your tyre pressure every 30 days and ensure proper alignment is done every 25-50,000kms depending on road conditions you usually drive at. More pot holes means more frequent visits to the tyre shop for alignment.
Cheers and happy modding. :)