I had Denon AH-D2000 with wood cup (from D5k) and LA pad (not full mod) for my primary headphone for quite sometime.
Between those two to my ear Mad Dog much more smooth and relaxing sound compare to my denon which I find it harsh sounding. This is funny because before I got the Mad Dog, I was pretty much 'in love' with my denon. I also notice right away is the bass which my denon has more impact and its just not as smooth (to my taste) as Mad Dog.
I'm not sure if I want to do full mod to my denon or just sell it to buy new amp for Mad Dog..
From having experienced a pre Lawton to post Lawton D7000 mod I'd recommend going for it. To me the change was large enough to sell me on the Lawton mods along with the angle pads. Have the mods on my D2000 as well and a wood cup mod happening next week. The bass of Denons is the sound I have come to appreciate as my favored signature.