Welcome to the club!
The wording of your question kinda confuses me, but you can get chromed 16's stock from the factory. If you already have the other ones, somebody around here would probably be happy to trade you for your rims + a couple bucks. That would probably be the least expensive way to go.
Do you want chromed or polished? The ones you can get from the factory are polished. Polished is alot lighter than chromed, but sometimes not as shiney.
How much heavier? If anyone has any chrome rims for sale email me at railfan37379@yahoo.com, and thanks for welcoming us to the club, we love our little hatchback/station wagon.