The only benefits of 93 octane to you would be:
- Higher "starting" octane, so the fuel could be older and still have a high enough octane rating for the sled. Even with fuel treatment, the fuel still degrades and its octane rating drops - it just takes longer with a good treatment. If you're storing or going longer between rides, 93 would be better at the end of a chunk of time (in terms of its octane) than 87. You still need to put fuel treatment in it.
- You *may* be able to get fuel with zero ethanol in it if you buy 93. Find out whether there are stations near you that sell non-ethanol premium or not. If not, don't waste the money.