I am running the CAI tune on 93 oct. Last night, I needed gas badly and drove into a full serve station. i told him to fill it up, but didn't say with 93. So I now have a full tank of 87 oct and do not have my tuner handy.
Well don't get on it at all. If you can find Torco additive, put some in. Don't try any other octane boosters though. They'll just gum up the engine. And switch your tune or get rid of the '87 as soon as possible.
I think you'd probably be ok if you drove like a grandma. The knock retard can make up for it under light driving conditions. But I'd still try and get ahold of the tuner just to be safe.