Can I adjust QoS Quality of Service Up/Down values in Netgear Cg3000 and CG4500 routers?

Hi,

Im looking to add Cox Premier internet at new apartment and wanting to buy either the Netgear Cg3000 or CG4500 routers/gateways.

But I want to know if I can alter specific Upload and Download speeds of ports using QoS or Quality of Service settings in the gateways.  Has anyone adjusted the QoS settings in these routers?

Thanks in advance,

Douglas