Does anyone know if i use both the wireless receiver and the ethernet cable to connect to an internet network (different provider) is going to be a problem or i will have better results? (for ex better speed)
you will want to check in "system preferences -> Network", make sure ethernet is first in the list to give it priority, otherwise it will use your wi-fi even with a cable plugged in.
if it's not in the correct order, click the settings button at the bottom of the list, and pick "select service order"