I use NF and it is very good !

 

a gallon of race gas a day, keeps the premature detonation away.

Well 93 will suffice, and 91 if your in a sticky situation. But yeah Don't put in fuel addatives, they don't do crap. And think about it, you pay about $8 for a bottle that treats one tank, and gas goes for about 2.15 for 89, and 2.50 for 93. Now to Supposedly increase 89 rated octane to 93 you would need 2 treatments so thats 16 bucks. therefore its cheaper to just buy 93, and for those days at the Track a little 100 will be fun.