Generally the Community Management Statement governs the occupiers of a development. The CMS will contain the By-Laws of the complex and should also contain the remedies available to the committee who governs the complex.
A manager generally would not have the power individually to remove a vehicle unless the committee has granted that power to do so.
Do you own or rent in the complex? If you own you could contact your body corporate manager to obtain a copy of the CMS.
If you rent you could ask the owner to get one for you.
Like all things it comes down to the fwit factor. If your onsite manager is a fwit well you may have problems, same if your an fwit, they'll give you problems for the sake of it. If your neighbour is an fwit they'll give the manager problems until he/she does something about it.
In my experience it is very difficult to remove a persons property from private (common property) without going through a fair few hoops first..........but it really depends on the type of complex and its history.
If you get a copy of the CMS I am happy to read it and give my interpretation of it.
Cheers