New City boss Manuel Pellegrini has splurged the cash on Spanish duo Alvaro Negredo and Jesus Navas from Sevilla as well as Stevan Jovetic from Fiorentina and Fernandinho from Shakhtar Donetsk - spending more than £80million in the process.
And Mourinho believes that investment on experienced players means people should expect more from City than his young Chelsea side.
"I know the players City have bought and they're players without surprises - they're more than ready," said Mourinho, quoted in the Daily Mirror.
"If you see their ages, their maturity, they're in the perfect time of their career to go to England.
"They are players at the top of their careers who don't need to adapt - experienced but still young, so I think they have bought very, very well.
"So of course people should be expecting more of them, with their experience, than my young team."
Mourinho added: "Young players need to learn, they need time to get to the top.
"But Navas and Negredo are to world champions, two European champions, Jovetic has been one of the best in Serie A for more than two years and Fernandinho has lots of experience.
"They bought very well. That doesn't surprise me, because they have the money to buy but also the knowledge. They have people in the club who know a lot about football.
"In my first spell you, the press, were always putting pressure on me saying, 'You buy this, you spend that, you buy the title'. So I hope now it's on the other side."
Chelsea have signed young players such as Marco van Ginkel and Andre Schurrle, leading Mourinho to conclude that celebrating the Premier League title come the spring would be his best trophy win ever.
He added: "When people ask what it will mean if we win the title, I say there are no ifs - either we win or we don't.
"It would be different. I t can be better because I always say that the best trophy you have is the most recent one.
"If we win this season, with this group, it will be the best for many reasons."