Nobody gives out specs for parts, particularly toy parts.
Non-replaceable things (as deemed by the company) are not encouraged to be replaced.
WowWee's no different than any other toy company in that respect.
I'd wager that NewBright sells a lot more electric motors wrapped by toys than WowWee does. Try finding spare parts other than a battery for a NewBright RC vehicle.
Update - just checked their site
Guess what it says.
* Please be advised that no parts are available for purchase.
ScottE -- collecting and building robots for 40 years - details in profile