I only commented on DIG in general, not the posted clip
Haha well to be honest, you do have some more work to do on that tone, but if you are willing to experiment, I think you'll get it quite good. I agree that it can be fatter or heavier... have you tried multiband compressing the lows? Instead of simply high passing the guitars, I tend to set the highpass much lower, let's say 90hz instead of 150 or even 200 as some people do, and just compressing the rest so it doesn't overwhelm. That way, even when playing melodies and stuff, I get the "thump" and stuff that makes it sound and behave a bit more like a real amp/cab.
Actually I found I had just turned the bass too low due to having problems with boomyness just early on with my knob fiddling. So here's a new version with the bass knob turned higher and some t-racks mastering action going on: http://dl.getdropbox.com/u/774335/I dig DIG RAIWHGAEGHA.mp3