Is there a true plug-n-play setup for a 5.7 with FI yet?

Hotwire sells computers for $670 as per there website. A tune/flash of your computer is $250.

A harness is $950.

Riddler

$950 for a manual or 727/904. $995 for newer electronic automatics. I went with a used computer from them for $300 because by the time I found a used computer, shipped it there and back, and had them flash it for $250 I would have about $500 in a used puter.
Contact Chris Squires on their website. He always responds and knows what he is talking about.