Some doubts about Loadrunner Controller


I'm using loadrunner controller, but I have some doubts and I'd like to get the answer.

The recomendation is to use two machines, one for controller and one for the agents to run the application. 

My question is ,  are we going to get different results ( big differences)  ?

Please, could you tell me if it is necessary to install the full loadrunner package or the Vugen SA is enough in order to run a remote machine as a LoadGenerator ?
In addition, please, could you tell me how to configure both machines ?
The one witht he controller use a proxy, and the ones with the agent use a firewall ( in this one I have the BPM and Vugen SA installed)


Many thanks and regards