The speaker wires connect to the main unit with connectors and not bare wire. Your best bet might be to splice the wires and add extension wire in between the splices. That's not difficult at all. It will, however, modify the original wire, so the unit won't be as-purchased if you want to sell it (or bring it back) - just something to consider.
So, you certainly can extend those wires. If you decide to get that unit and still don't want to use the wireless option, let us know if you want any help with splicing the wires.
