Your best bet is to figure out what octane is, and how it works. Maybe go to howstuffworks.com.
A real quick explaination, and answer to your question is no, higher octane won't do anything for your car. Octane makes fuel less combustible, allowing for greater ignition advance. Since the RS's ECU is not programable, you will not get any advance.
By the way, this topic has been beat to hell, and the only people that believe higher octane is better are those who use it, and just think that. Never any evidence has been put forth to confirm anything. Well...besides the ever reliable butt dyno.
Just don't go with that 85 crap sold in CO. Your ECU will act like windows 95. 87 or 89 if you're worried. The oil companies are to blame for people thinking high octane is really premium. It's just that, higher octane.