Pete you claim to be member of several forums, you should know the drill of what happens when a newbie to a site with total disregard of the membership already here , showing up & challenging the community without you even knowing it's makeup.
Now imagine us & you a new guy we have never seen before throwing out a challenge as if what you propose has never been done, to people with many years of 6.5 experience, collectively we have centuries of experience here with the 6.5 and all things pertaining to vehicles.
Had you come on-board asking why all the buzz over the ATT vs the HX turbo you would have gotten a wholly different experience, but to with a 1st post as challenge over a that was turbo years in the making & lots of R&D into it to make it a user friendly setup is not a way to break the ice at any site. Cussing is not conducive to folks wanting to help out either
As for the HX-35, it's been done, the HX-35 works, it isn't as intuitive of an install as the ATT is, I don't recall anyone running it at 20+ psi which it is capable of doing without lowering CR, the ATT will get you to 100 mph with just 10 psi boost, so same net gain as the HX without stressing engine any more than necessary.
As for your co-worker doing a comparative install, take a new HX-35 out of a box as delivered (or a used one that looks exactly how a new one would arrive) you don't get to assist other than a phone call or posting questions on a web site like here, and have her install it on the 6.5, vs . an ATT as delivered and see which one is more plug and play ready to go, stop watch for both begins once the old GM turbo is off.
I've done a few now, so my time is not a fair comparison but 1-2 hrs is avg time for me to remove/install & be road ready in 3 hrs after buttoning everything up, if I was in a race against the clock I could do it in less barring complications getting the old turbo off, but I've also been wrenching the 6.5 since 2000, and machinery in general since maybe 1966 with my 1st bicycle "overhauls"
