Have you tried doing anything with the comp off? What were the results then? With a slow attack and slow release, I'd expect the low end to get a little more tubby and uncontrollable, IMO. Having it get a bit muddy or distorted doesn't sound too far off from what I'd think would happen. What happens when you put the attack and release at the mid point of their sweep? I, too, think ITP up too much doesn't sound good, even if the transients are intact...IMO it sounds artificial, for lack of a better word. I like the ITP slider at about the halfway point or just north of the middle.