eclein,
You can see, from the picture, that I am currently running my M451 as follows:
Left: Sonicap with Platinum bypass
Right: AuriCap
My initial impression: The AuriCap is a fine capacitor AND the Sonicap is a fine capacitor. I would also agree with the earlier post about them having sonic differences.
I just don't want you to think that your current setup is lacking - it's not.