Complete junk! Look on the forums CGP, Here, GPONA etc. If it isn't ZZP, or CT its fake crap. (Unless its custom as in someone in the GP community made their own kit).
Usually around the fall time is when you see turbo kits all over the place.
Myself and two others that I know of found kits for sub $2k with low miles 2 years ago. 8+ kits went up for sale that year it was nuts!!!
Now you can make 300whp turbo very easily without any engine mods what so ever.
I will say this don't go into a turbo project without a little savings in the bank for backup. Everyone's build is diff and things do break. It's not a kiddy club but if you stay around 10psi on an avg kit you shouldn't run into many issues other then trans. Everyone is going to try to scare people away from turbo setups and its sad really. Granted you should know the risks and such but I mean come on. A few people blow they're trannies within a month of being turbo and everyone goes ****wild against them. My first non HD trans with 92k lasted me 8 months of everyday beating the living **** out of it. Every trans is diff you never know what could happen but guess what **** breaks...
If your goals are sub 300whp don't bother going turbo.