My question is if I bought a modem router combo, and I was hardwired into that, would I get the same result as being hardwired straight to a stand alone modem?
I'd say no but you probably couldn't discern the difference.
A standalone modem has a WAN port.
A modem/router has LAN ports.
A cluster of 4 LAN ports on a router...either standalone or combo...is a network switch to route data either internally onto your network or externally to a modem. There is also a demarcation point within a modem/router to separate the modem from the router. That way, your router isn't exposed to the public.
This demarcation point is probably also a layer-2 switch or some type of layer-2 network connection.
Either directly wired to a combo or a standalone and then a modem would still involve 2 network switches. Directly wired to a modem is just one network switch and faster because it's just layer-2. Layer-2 is a lot faster than layer-3 (network).