To start with a five star team immediately in Career mode, go to the team 
management screen. Put the bad players in the first eleven so that your team 
will be a four star team. Then, go to Career mode and your team should be there. 
Save your career, then go back to the team management screen. Put the first 
eleven players back, save it, and you will have the normal team on friendlies 
and your team on Career mode. Additionally, you can make any team have full 
stats by editing each players stats and upgrading them to 99. However, if you 
start with that team in Manager mode, your salary will be high. Make sure to cut 
their contracts down as soon as possible.
Use the following trick to be any team desired in Career mode without buying 
better career teams from the Fan shop. Go to team management and select a four 
and a half or five star team. Put all their worst players into the starting line 
up. They need to be at about four stars or below, then you can then use them in 
Career mode. When you have begun your career you can change your team back.