Shuld we use remap tablespace?

We are trying to export the audit trails from one of our instances and import it to an other instance on a different RAC. We also want to import the audit_trail on a different tablespace.
In the origin audit trails are stored into system tablespace. We want to import audit trails into a custom tablespace what we previously configured to store the audit_trail.
We have done the export, but when we try to import using this command: impdp '"sys/pass@formacio as sysdba"' directory=IMPORT_AUDIT dumpfile=AUDIT_%u.dmp logfile=AUDIT-import.log full=y parallel=2 we see that system tablespace is growing, so we assume the import is saving the data inside system tablespace. Furthermore, our custom tablespace "AUDIT_TBS" is practically empty.