Re: Normal Unleaded or Superunleaded for 3.0 166 super which is best?
Maxol in Ireland, are currently selling E5 that has a 5% blend of bio-ethanol and has a 99.2 octane rating.
Again you can get a car remapped that will take advantage of 98 octane but also accept 95 octane as some remappers are able to do.
No need to be locked into 98 octane only, unless thats really what you want (a more detailed mapping could be possible in this case).
The cars are equpped with knock sensors and the ECU is capable of advancing ignition timing under controlled paramaters..
A remap would add extra advancement than the factory would provide by default since they have to play safe due to concerns about fuel quality and conditions for vastly different geographical regions.
I'm not a doctor - but I really do recommend braking later