Getting ETL from redo log data

I'm designing an Inmon G.I.F like data warehouse and need to source data from a OLTP CRM like bespke app that I don't want to mess with. I've been investigating tools that can do changed data capture (CDC) from redo logs,no need to use Oracle's CDC. Using some kind of CDC reduces your data warehouse load sizes as you can just grab the deltas, Oracle RDBMS has built in CDC that comes in the Ent.Ed but may need DBMS streams and other configuration
Attunity CDC can be installed where the staging area is (no installation required on the machine where Oracle lives) Access to the redo log is through a SQL*Net connection.

Check out Attunity CDC and GoldenGate(now Oracle), superior to built in Oracle CDC. Still need to set the DB to add a supplemental log destination

ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;

Attunity Pricing is based on the h/w config of the ETL platform where Attunity is installed; i.e. #cpu's and how many Oracle DB's get connected to from the ETL platform