I'm running the 1.15 ar with Stg I's from Bean. Its just a hair laggy on the bottom end but if I pin the throttle and hang on for dear life I can get 36-37 psi out of the stocker, I'm afraid if I went with the 1.0ar that I would be 35+ psi just on mild throttle stands. The biggest draw back with the stocker it it cant handle extended run time at 25 psi or over..... it will kill the thrust bushings and bearings. I am non I/C'd with my current set up, I havent dyno'd so I dont know where I am hp/tq. I do know that I can pull what ever I want and do it side by side with a 6.0 or a Cummins. Now I cant walk with a highly modified newer diesel but ****, those guys are damn near 350 hp off the showroom floor. Ive been real happy with the performance aspect of my truck since the upgrades.
I would recommend a HPO system and possibly a fuel system before the turbo, I think with Stg II's you'll find your HPO a little skinny, which may lead you to think you need a turbo, but if you keep that injection pressure up high enough you'll have better atomization upon the injection cycle, thus you'll get a better, cleaner, more complete burn.
JMHO.....