When I was considering both units as a package to install in my truck I called their tech line and asked a lot of questions. They were unable to explain their product and how it would function in my truck, or change the functions of my truck in programming. I have a couple friends who have the pucks in older models than mine who are satisfied with the performance gains, I have a couple friends who are not-surging issues,etc. I did have the pair on order via a supplier of their products, and was in a holding pattern waiting for the 06 model products to be released. The more I thought about the answers I got from the tech line, and the answers I did not get, along with the rail pressure questions that seemed odd, I decided to go with other products. Just my 2 cents.
CD