Load balancing doesn't always mean equal... you'll never see the full 100% of any connection, more like 80% at best.
unless you're load balanced and seen as a single IP address and the loadbalancing is done per-bit, not per-session, you should get near your theoritical max. This also assumes you have a full-duplex connection.
on the wireless and cable combination, without some 3rd party solution, the OS itself probably won't be able the handle the routing and the connection tables properly.
Just my 2 cents