EPL will start again starting next week with Chelsea and MU will start the competition in a community shield event. Both team has finished their pre-season matches and so far, both are satisfied with their squads, even though no star players for MU this season. I don't think buying a star player will increase your performance significantly. Take an example of Real Madrid. Even though they have bought C. Ronaldo and combine him with other talented player, in the end, they couldn't get anything this season.
Oh well, let's see whether this season will be a tight one again or not