I've seen China based injectors f**k motors and flow all uneven without use, if you go down that route get them flow tested first. Stick to Japanese products in my opinion, Nismo if possible, saving $300 on some injectors may cost you 3k in the long run. Also, the price between 550cc and 800cc is not much but gives you the room to push some more power later down the track. Stockers are about 410cc, so moving to 550cc is a supersized GT-R injector.