Which Router & Modem Should I Use?

Hello, I am currently paying for a 400 mbps connection from spectrum. When they set it up they gave me one of their standard modems (Arris TM1602) and their standard routers (Sagemcom RAC2V1S). I currently have a Netgear C7000-100NAS router modem not in use. Right now I get up to 475 mbps max and was wondering if I should switch the router and modem Spectrum gave me and replace it with my Netgear one. Wanted to hear what I should to to achieve the max mbps I can. Thanks.