Just thought I would throw this up here for informative purposes. I went to the local grain dump station earlier today and put my car on the scale. Now its not EXACT but I believe they are within about 10 lbs most times. Now on to the results!
The car is an 05 Apex Silver GSR. Regular halogen headlights, non SSL. Still has all the factory

Mods that matter:
Hks intake
Hks Downpipe and exhaust
Helix test pipe
Megan o2 housing
Gutted trunk (I.E. no carpet, spare tire, but does have a socket set I always carry)
Removed back seats and seatbelts
Removed rear speakers
Carbon fiber lip and trunk lid (no wing)
Turbo XS 3.5" IC
BFG 225/45r17 Drag radials (may seem insignificant but these are a couple pounds lighter than the stock tires each.

Results!
Exactly 3100 lbs with a hair over 1/4 tank of e85.