Unfortunately nobody wants to do all that work twice if they already have the motor out. I run the stage 1 in my fresh motor that Unlimited built and under the curve the truck just has stupid smoke clearing capability (until the 38r's turbine gets overwhelmed). I swapped in the exact same injectors and turbo from the tired motor and am still waiting for break-in, but so far the truck flat out impresses me. You really have to do something wrong to get ANY smoke and it cruises down the road at 650 degrees at 70MPH on 35s. Boost is down 2 psi compared to where it was before on the highway under the same conditions while running 100 degrees cooler. I'm not trying to sound like I'm giving a sales pitch, but I am really picky and this thing is doing exactly what I wanted it to.
I have not have had any complaints and I know of 12 cams installed in running motors as of right now. There are 4 more in projects that aren't finished yet.