I have improved the overall enjoyability on my 04 QC 3500 SRW by adding a VanAaken duration box to it. I had been running an edge EZ on #4-w-Dyno numbers of about 300/600 and was happy but lets face it - more is better. I put the VanAaken on and backed off the Edge a bit and am happier. On setting #1 the truck seems a little smoother and this is what I drive around on. On setting 2 the truck is much faster and for the first time smokes when I stomp it (although I would have to be convinced this is a good thing). I will have dyno numbers in the next month or so and will post them as I have for the Edge EZ addition. I have been told that VanAaken will, at some point, manipulate the timing by taking the box back and reprogramming it which I am really looking forward to.