Got my Tunes!!

[blackfx4ny]

I just want to say, these things are awesome. I got an 87 performance, 87 economy, and 93 performance. The 93 pulls so hard up top it's ridiculous. I love it. After one tank of93 (already had it in there) I switched to the 87 performance. Also great. Now I am in a pickle. I need more gas. I want 93 because it's just so much fun to drive. What do you guys let your fuel gauge go down too before switching to a tune requiring a higher octane? This week is the first time I've had 87 since November. I am at almost "E" right now. Think that's low enough to go ahead a switch?