Cool! I did't know where to start as far as the kit prices go online, so sorry for any confusion. I can sell it for $519 + shipping.
If you want to buy from groupbuycenter.com, go ahead. If you want to establish a customer relationship with a premier tuning shop, buy from me. If you have problems with that kit, good luck getting groupbuycenter.com to even answer the phone.
Also FYI, that's the import kit and you'll need to buy different fittings for your DOMESTIC car, the fuel connections IIRC are different and the import NX kit only has 3 jets--35,50,75--you'll need to buy anything over that. This kit comes with jets for 100 and 150.
There are ten million sites like groupbuycenter, run by people who make 10 bucks on your nitrous kit and don't have a shop, technicians, or a purpose. They undercut in the industry and feed off the scraps.
If I was you, I'd buy from a place where I KNEW I had a CEG'er on my side.
Thanks.