Here's a proper lipo powered car:
"Kokam Li-Po batteries have arrived - 200 Ah 3,7 V cell with weight of only 4 kg!"
http://www.ad-pecjak.si/ECO/newsEespace.htm
"We drove 193 km on pure electric drive without charging the batteries and they still had 3,56V per cell what means about 20% of the total capacity!!!"