the extended batteries for the Nexus are bullsh**. normally, an extended battery is at least/close to double the mAh as what the stock is. these 2100 & 2300 batteries are a joke.
just FYI, there are no antenna contacts in the battery door so even if you leave the door off you can still get a signal.
additionally, if you don't mind leaving it off & doing a slight mod, you can get a generic Droid Bionic 4000mAh battery for $12 online and use that instead. the Wh isn't quite as high but it's still 3.7V and will last much longer then even that 2300 one.