Today's update. I had AAA take my Tahoe to Lethal Performance in Morristown, TN who did the preliminary tune with just the computer. Checked with them later and they've had it running and idling and I think they even drove it into their secured parking. Hopefully tomorrow they'll call me to come get it. They're going to tune it for the 93 octane. Later when I can I will see if I can run E85 and get it retuned for that. I'm hoping (someone let me know) that both programs can reside in the computer and it'll switch between them based on E85 detected like stock does. Also, being cheap it wouldn't be a bad thing if I could run regular which is $0.40 cheaper a gallon.