everyone I know still runs 1-2gal of race about 6lbs for piece of mind.
If your worried about metal wear and want some added protection there is a product called SFR (superior friction reducer). comes out of somewhere in MT I think and can be found on line. It is pricey but it works, the oil molecules are much smaller than normal and stay in the metal. I have proven this stuff to be worth it. Just add one once to every quart in normal engine oil (crank case) I would add about 2 in 10 gal of gas in a sled.
Took an old junky car and after treating it with SFR I dumped 1/2 gallon of antifreeze in the crank case and drove it 3 miles, left it running drained the oil/antifreeze and put new oil back in the car, months later sold the car and not sure how long it lasted (at least 6 months). My mom had a 83 chev conversion van that was ran down to 1 quart of oil and the oil pressure would drop to zero and the motor would rattle when rapped up. She did it 4 times and eventually started smoking, started to take out the oil rings but still ran great. Once I put a bigger cam in a 84 camaro I had and when I fired it up it said it had oil pressure(the gauge was in the same spot as when I shut it off) but I failed to get the distributor locked in the oil pump, I did the cam break in then took it out on the road and rodded the pi$$ out of it for 12 miles before the motor went because of NO oil pressure, the few other times not running sfr when my oil pressure dropped it only took seconds to take out the crank bearings.
This is what really got me, a friend decided to throw some in his 03 YZ450 (1 once) in the case, immediately the clutch started slipping, so we drained it and put new oil in, still slipped, I took the clutches out and cleaned them with soap and water and a hot pressure washer, and then acetone, cleaned them three times before it finally started hooking up in all ranges.
I have also heard of friends cars getting 1-3mpg better but have never checked things that close to know myself(my driving is to erratic).
