Not sure of technical differences in garret 3794 vs marks stage 2 3794 but this was posted by towu4free on page 32 of this forum.COPIED FROM MARKS POST IN DURAMAXDIESEL:-----This is a 65mm turbo and would be a good choice for what your looking for.
As far as this versus the out of the box GT3794va, the cast version is not very good above 500hp which is where this version really shines. Mine is on tune 4 everyday at 535hp and it makes 30-32psi at 1150egts. Mine doesn't go past 1400egts till you get up to that 650hp range.
DMax497- Honestly this would be the turbo choice for ya if you want a vgt and with that fueling I would think 700hp would be a nice driving truck.