Ok, here you go:
The reason the GReddy kit is legal is because it has aquired a C.A.R.B. number. The California Air Resources Board does not issue numbers to everyone...except those who have the time and money to get one. In reality, the GReddy turbo kit itself does not pollute any more or less than any other kit...they just spent the time and money to get the number. As soon as you put a blow off valve on it, you have voided that number.
Now, does this mean that your car will pass the sniffer test when you go for a smog check? Absolutely not. That C.A.R.B. number applies to BONE STOCK cars, with the bolt on turbo kit, and NOTHING ELSE. If you have an exhaust on it, or a V-AFC, and have adjusted your a:f ratio...you may have voided your legality.
I am sure you are not going to leave the rest of the car stock, or run with no blow off valve...so with that said...screw it...get a better kit, get more power, and when sniffer time comes around, do what ALL other turbo owners do, and bribe your speedshop to send you to their smog hookup.