To start I'm a huge fan of your work. I've been a lurker on your site for some time. I owe you guys a call for some other stuff here sortly.
Personally I dont see anyone getting 600rwhp off a stock motor safely. Everything to date (as far a stock motor and forced induction goes) is 600Bhp maybe 625 if your lucky. Anything after that and your riding the edge IMO. also what kind of abuse could that turbo take off road?
First hard hit and you'll know if it was a bad call. I think your stepping way out there to build a "budget" turbo making that kind if power. I know realistically if I was to approach a turbo set up being cost conscious I doubt I could afford a new motor when I blow up the stocker. It's just the deep end of the pool and you have to pay to play. As a shop it would seem like unnecessary liability to install a kit like that on budget minded trucks. If anything goes wrong internally you won't have many options (as a shop) to fix it. I didn't buy the Whipple until I knew I had the funds to replace the motor if it grenade it.
Can you imagine all the power hungry drivers turning up the boost, kicking a rod and towing their trucks back looking to you to fix them? Not this guy... One thing I have learned in all the years building cars is that you build what you can afford to fix. Budget and turbo does not make sense IMHO.
You guys do make a kick ass roll cage that come Christmas time I hope will be in its way to my garage.