Unless the older metal fuel tank weighed something like 80kg's, there is no logic in that alleged logic. Knowing Maruti and their love for lighter and not necessarily stronger metal , even the older metal tank would've weighed as much as the present plastic one. You know what i mean . Plus, cars gain some weight when they are stretched. The new Swift has been stretched 50mm and has paradoxically reduced weight. I know the response to this will be that Maruti are using stronger but lighter metal , BUT had Maruti used such a metal they would've stood atop the Qutab Minar and shouted about it. Just like their marketing department has made people talk non stop about plastic tanks. So, the light Swift has become lighter. Gurjinder.