I just installed my Predator in my 07 Silverado Classic, 2500HD, 6.0 Gas, Auto.

Is iit alright to tow my travel trailer with the 87 Octane tune installed?
Or would it be better to install the Performance tune and run 91-93 Octane?
Or would it be wiser to return it to the factory tune?

I just don ...

Looks like I wasn't turning the key far enough. I was only turning it to "ACC" and not "ON".
Tried it again with the ignition "ON" and it worked. Thank you for the answer.

I just got my Predator today and after thoroughly reading the manual decided to try to install a tune.
Everything worked just like the manual said, backed up the factory stock tune without a hitch (seemed to take about 3 minutes or so).
Went to install the 87 Octane tune and after a few moments of ...