Porsche recently unveiled their new weight-saving lithium-Ion starter battery as an option on their 2010 lineup.
The battery is slated to sell as an option for about $1,900 Euro ($2,600 U.S.) for those that need to shave some weight off their cars for track day.
Total weight of the battery is 13 lbs as compared to 35 lbs of a conventional lead-acid battery. Read more here:
Porsche