Interesting, sounds like Milltek was able to tune the sound exactly right, that's the nice thing about going with their setup.
This article gives a nice overview of muffler versus resonator: http://www.americanmuscle.com/mustan...ifference.html
The challenge is figuring out exactly what frequency the factory resonators are designed to tune out. It's very possible they are targeting the "drone" rather than the "rasp".
Once I do the muffler-delete on mine, I'll definitely provide some sound-samples and feedback.