Praise be to Allaah.
The Sunnah is to pray two Rak’ahs after making wudoo’, because of the hadeeth of Bilaal mentioned in the question, and other reports. But it is permissible for a person to pray as many naafil prayers as he wishes in addition to the two rak’ahs, except at times when naafil prayers are not allowed.
And Allaah is the source of strength. May Allaah bless our Prophet Muhammad and his family and companions.