Whaddya wanna know? The kit was originally developed by Leading Edge Performance in Temecula, CA, for application in turbo EJ25 sand rails.
Rally Knight has worked with LE to adapt it to their rally cars, and have submitted samples to a testing lab in Arizona that is sanctioned by CARB to test to their standards.
Being in MA, I think you needn't worry about CARB legality, arguably one of, if not the strictest standard to meet.
The kit I'm getting is the first run of their 300HP street kit. It uses a watercooled T4 hybrid (T3/T4, I believe, but don't quote me), custom fabbed IC, Motec M4, and custom up/down pipe, cat back pipe, etcetera. All sensors needed to run boost are included, like a GM 3bar MAP, baro sensor to allow compensation for atmospheric changes, etc, but reuses stock sensors as well. (cam and crank sensor for sure, will get complete tally of what's stock vs what's replaced when my car gets back to me).
I won't lie, my price is cheaper than what you'd pay, because I'm the guineau pig. I'm Rally Knight's first commercial customer, and up until now, their supplier has only built for their rally cars. So they're going to take extra care and time to build mine up, and make jigs for future street kits.