Want to tone down my exhaust overall volume

[mrzzzr1]

History:
I have full length tube headers and used to have flowmaster exhausts.
Last month I replaced the flowmasters for Corsa's to reduce/elimiate a resonance/droan sound at hightway cruising speeds (65-80 mph in 6th gear)
Corsa told me that it would be agressive without CATs and they were more than right.
With the Corsa it is somewhat quieter at steady highway cruising speeds.
At accelleration 1/2 throttle - to full throttle it is now louder than ever. Runs great and sound good for a race car but with the wife in the car it is not just agressive but extremely agressive, plus I don't want to advertise to every cop in ear-shot that I just jumped on it.
My mechanic and I are now discussing adding some short cats somewhere probably into the headers. He recommends not putting my original factory headers/cats back on but keeping them on the shelf incase I ever want to restore the car back to stock. Plus more problems if the original cats fail and have to be replaced.
Please help if you've solved the same problem or if you have some good advice to share. Thanks in advance.