get a baseline dyno while its normally aspirated. if the numbers are off, then you shouldnt put the turbo on.

on a dynojet, your stock LS should be putting out something in between 110-120whp

do a compression test as well.

if your baseline and compression numbers are where they should be, i always recommend installing the gauges and fuel management prior to the turbo install. what fuel management are you going to run? i recommend running a stand alone system of some sort. no piggyback computers or rising rate fuel pressure regulators.