Around 20lbs for the street tune and 25 for the race tune.
You should be fine, the kit comes with evolution wastegates that include 5psi springs that you can install. Provided that everything is installed correctly you should be able to get 20psi from the kit by regulating the turbos to 5psi. I have the kit on my car, the lowest bost I could get from the turbos was 11 psi 25 psi compounded, but I had some other issues. There are quite a few cars with this kit on the street with stock motors, and 90% of them are running meth injection to crank up the boost. Just out of the box on the low boost seeting ou should see between 650 and 700 rwhp.