I don;t think it matters that much what you go with, I went with the Ford Racing via CoolTechllc.com as I live in the Republic of California. I really doubt a smog tech would know the diff on these cars. But after passing for a couple cycles on a Z06, and trouble passing with the new OBD2 rules for readiness ,I decided to go with Ford.
If I didn't live in Cali I would go with Torrie's or John's tune. Just my opinion. And BTW I know for a fact John's tune produced more HP/TQ at a dyno day a few years ago, than some others. We did not have an example of Torrie's tune that day, but is shows what the tuners can really do. I feel the diff with the Ford tune at roll on for sure, you will not be disappointed, but I also assume some is left on the table. I follow this stuff pretty close, So my Choices would be Torrie/John/Ford.