my car has a ER front end, CF hood and a CF trunk and an after market exhaust and wheels it is probably 80-100lbs lighter than stock in various parts of the car. I gradually upgraded it all along with so many other part of the car that it is hard for me at this point to compare it to stock.
Race seats, deleting back seat, lighter battery are all fairly easy ways to cut weight but some have noted, eliminating the sunroof would be noticeable.
MY Build Log
08 AW 135i | Cobb | ETS FMIC | ER CP w/ Tial Bov | AR Catted Downpipes | Berk Mids | Meisterschaft GT SUS 1M |M3 Control Arms | M3 Sways | M3 Rear Subframe Bushings | Wavetrac LSD | AST 4200 DA Coilovers | HRE R43 | Hankook R-S3 |Full BMW Performance Interior | Revozport 1M Raze Aero Package in Satin Carbon |1M Body Conversion|