Syma S107G UPGRADE Battery 240mAh 3.7V 30C
The 240mAh is the recommended battery upgrade by Syma.
I sell them but am out of stock right now, they are stellar batteries, received tons of great feedback from them! I have a website dropping soon http://www.symabayrc.com/
& have some things on eBay http://myworld.ebay.com/cnote4
but are higher in price due to their fees...
That 200mAh is going to be too heavy. I tried those and it adds a slight amount to it, but nothing like the 240 which is actually lighter and smaller than the 240mAh.
Hope this helps you and anyone else wondering the same!