You are going to spend 17k for 150hp and some check engine lights? you should have just bought a cts-v if its speed you want, or an used GTR. I cant see 17k for an un-proven turbo that may have a good chance of causing more problem for you to spend more money on.
I've heard nothing but bad stuff about this kit. I'd do a little more research or see if a shop will do a custom build for you. I have no clue who would do it in Poland but I know JE import performance in Baltimore would be up for the challenge and would do a great job.
I have a twin turbo kit with a fic tuning i will sell for 6500 it made 552 rwhp and ran with no check engie lights for months. I built my motor to run a big single turbo but no one in the country can tune it. pm me if you want anymore info. 763 202 0445 James