I ran 87 octane in my RS all it's life, except on trips to Colorado. Nebraska only goes down to 89. Colorado has 85, and my parents use that in their Forester with no problem, but the last time I put it in my car my front O2 sensor coincidentally failed. I can't prove it had anything to do with it, but wherever I go, I try to stick to the same gas.
You can probably do Omaha to Denver in a day; just watch for cops on I76 in CO. I've never seen so much as a speed trap in Neb.
And there's no reason to be giving a normal RS 92 octane. Run it till it's on E, put in 87 (or nine, or whatever you get out there) and reset the ECU just to keep it from having issues.