DO NOT RUN AVGAS IN YOUR PREDATOR-
I will totally agree with ML....But I bet you didn't know that the Toluene in the AVGAS will destroy seals in your engine given time.I am a commercial pilot for 18 years,and we have put Avgas in just about everything with a spark plug.
Also the lead deposits will build up over time and cause problems in some engines.I'll agree occasional use wont kill it,but push your luck.
I have been running 110 unleaded in my ride with great results,however I prefer 104.
As for the high octane causing your engine to ' run dryer ', I as well as several of the a&p mechanics I spoke to about this just couldn't see that one.