Hello Danilo,
there is an old RFC about this
http://tools.ietf.org/html/rfc1245
bandwidth comsumption is not an issue because averaged over 30 minutes timescale it is low.
As a worst case you can use 40 bytes/route.
CPU and memory usage will increase moving from NSSA to a normal area.
LSA type 3 inter-area can be filtered or summarized.
LSAs type 5 will be accepted as a whole or filtered all (if using some form of stubs).
Hope to help
Giuseppe