the benefit of removing your spare tire is minimal.

with that said, i dont have one in my car h:

now if you dont care about comforts, gut your interior of the carpet, sound insulation, door panels, headliner, rear seat console everything.... which will still provide you with little benefit... and then remove your AC and PS...

my friend told me his friends take off their wipers and mirrors at the track and it acually helps their times (not by a huge amount but some...) cuz it reduces drag. havent bothered trying it myself.

and i saw an ITR in honda tuning mag with a motorcycle battery.... not enough to power a ton of accessories but if you are just driving your car, no amps etc its enough to start it.... and thats lighter.... still minimal to zero difference but the guys that are serious about weight removal say every lb counts :dunno: