FI and never look back. I have the first kit that was not assembled by FI. Technically it was the third kit that was installed. I have 16k miles on the kit and not one issue. I am making 556whp and 552tq on 100 octane. The service from Tony and Sebastian is top shelf. Let's put it this way, Tony is not just the guy that built my turbo, he is family. If he wasn't, there is no way I would be going to ZDayZ!
You should go visit his shop and Specialty Z as well. If you do, it's all over except for signing the check!