Is having high MEMORY_TARGET value advantage

We are upgrading from 9i to 11g ( old box of 32 bit to new 64 bit box ) using export and import) this week end.

Current

SGA_MAX_SIZE is 11,500MB  ( 11 GB)

SHARED_POOL_SIZE is 512MB

PGA_AGGREGATE_TARGET is 600 MB

I have almost 64 GB memory on the new box. Setting high value ( say 32 GB) to the MEMORY_TARGET will be helpful in 11g? We do not have any major performance issues in 9i now. Since 11g has automatic memory management process, I would like to set the high value and assign shared_pool_size, pga_target and sga_target as 0 on the new box. How about sort_area_size?