BATTERY
Stock: 27.250 kg (60.02 lbs) -- 90 Amp/Hr (note; my oem battery weighed 55.4lbs)
http://bmwfans.info/original/E92/Cou...1/ill-61_2091/
Voltphreaks vph900 (7 lbs)
https://p10.secure.hostingprod.com/@...products_id=80
Cost: $1000
Weight savings: 48 lbs
cost/benefit: $20/lbs