The Citizens, under new manager Manuel Pellegrini, recruited Sevilla pair Jesus Navas and Alvaro Negredo during the transfer window, as well as Shakhtar Donetsk's Fernandinho and Stevan Jovetic of Fiorentina.
Despite losing former captain Carlos Tevez to Juventus, Aguero feels that City have a better chance of regaining their Premier League crown this term.
"Carlitos has moved on and he was a great teammate," Aguero told The Sun. "He's going to be missed but we wish him the best in his next step.
"But I always keep a close eye on Spanish football and Jesus Navas and Alvaro Negredo were two of its brightest stars.
"Having them in our side makes us stronger - the same applies to Fernandinho and Stevan. They are amazing players."
City currently sit third in the table.