with a good turbo you can make near 500 on right at 20 psi, say around 480, like a t67(which is the largest turbo i would do for a daily street car) I wouldnt do the darton sleeves, maybe something more along the lines of golden eagle, aebs, or benson. Compression isnt as big of a deal really these days as long as you dont do something like 11.5:1. your gsr crank will work perfectly fine, no need to search and buy a type r crank, tons of people use LS cranks, all of the honda OEM cranks in a b series will hold more horsepower than you can throw at it.