you can upgradre your firmware
My out of the box bb 8320 actually had bb maps installed despite me having the orange branded model. But it was a really old firmware version so it couldnt do anything with it of the "smart phone" variety.
So i found this link
and upgraded to the lastest firmware (4.5) and now everything works great, i can connect to my wifi network and watch video on it. BB maps however is installed but i cant access it.
The only firmware version i could find is intended for some Indonesian vendor, it was impossible to find the updates for the uk version. You just had to delete the vendor.xml file though and then it's fine to use.
Anyway, bb maps is shit, googlemaps for me is much much better, you get aerial photo's as well