first, remove all the stickers.
Things to consider:
- the spare tyre
- back seats
- swap the driver and passenger seats with some semi-buckets and/or buckets (e.g bride brix on driver's, bride ergo's on passenger)
- remove unnecessary boom boxes in da hood
- steering wheel, swapped to something lighter. momo, buddy club, etc.
- air conditioner
- swap to light weight materials if you must, i.e. alloy, carbon fibre, aluminium materials.
that's about all i can think of right now.