I've run MS109 @ 1.71bar without a problem. Though I have not tested it for extended period at that boost, I know that I had no detonation, etc..

I just don't see why you need a leaded fuel for a car that makes ~700rwhp with a very good tune. If the tune sucked I could see the need for the extra octane, but realistically you could get away with MS109. I know your tune is spot on because Todd did it so that shouldn't worry you.

In my brothers car we only use C16 in the nitrous fuel cell and we run 104 or MS109 in the gas tank and it makes 839rwhp on LOW bottle pressure. Nitrous and tunes can be unpredictable when your fuel side is high pressure instead of low pressure so we always have the extra octane to be safe... Then again we also hit the car with 300+extra RWHP so the amount of cylinder pressure spike that it sees is EXTREMELY high.

Sean I'd honestly say that MS109 would be your new best friend and the car may actually feel a little faster. Plus you save $4 or so a gallon.

 

Chris,

I usually my C 16 with the pump gas that is already in the tank. Rarely is the tank empty, so I like to get the highest octane possible. 109 is actually about 10 octane less than C 16.