The arrivals of Carlos Tevez from United, Emmanuel Adebayor and Kolo Toure from Arsenal, Roque Santa Cruz from Blackburn and Gareth Barry from Aston Villa should certainly see City improve in the new Premier League season starting this weekend.
However, it is not the signings themselves that have got under the skin of Manchester United boss Alex Ferguson, who is plotting a title defence without world player of the year Cristiano Ronaldo, sold to Real Madrid, as well as Tevez.
What really rankles at Old Trafford is City's assertion that they are about to challenge for a place in the top four, and ultimately United's position as the biggest club in England.
City tweaked United's nose when a huge banner was erected in the city centre showing Tevez in a City shirt with the slogan "Welcome to Manchester" underneath his photograph - a cheeky reference to the fact that United's home of Old Trafford is actually situated in Salford, outside Manchester city limits.
"They are a small club with a small mentality," responded Ferguson. "All they can talk about is Manchester United."
He continued: "It will not be easy for City this season, and for me they don't even come into the top four equation. For all the buying they have done, Mark Hughes still has to find the right balance, and what's he got - 10 strikers?"
Since Sheikh Mansour bin Zayed Al Nahyan took control of City last year, manager Hughes has spent over 220 million pounds on new players, including the British record 32.5 million he paid for Brazilian Robinho at the start of last season.
Anything other than a top four finish will be regarded as a failure at City, who last mounted a realistic title bid in 1976-77 when they finished as runners-up to Liverpool.
They have not won a major trophy since the League Cup in 1976 and since returning to the Premier League in 2002, their best finishing position was eighth in 2005.
Hughes, a former United hero under Ferguson in the 1980s and 1990s, is under no illusions about what is expected of him.
He told reporters recently: "I remember the pressure Alex Ferguson was under when I was a United player and he went four years before winning the FA Cup. The first trophy is the hardest. Then success becomes a natural thing because you have experienced how to achieve it.
"I know the pressure I am under. The owners want to take this club into the top four and Champions League very quickly."
To do that City will have to to dislodge either United, Chelsea, Liverpool or Arsenal and only one team - Everton in 2004-05 - have managed to do that in the last six seasons.
Despite the loss of Tevez to City and Ronaldo to Real, for a world record fee of 80 million pounds, United can be confident they have some outstanding young players coming through.
If free signing Michael Owen rediscovers his old scoring touch alongside Wayne Rooney and Dimitar Berbatov, the effect of Ronaldo's absence and his goal contribution will be diluted.
United are bidding for a fou
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