after having my speed3 for 6 months i finally tried putting the VP racing 95 octane in, to my surprise I'm getting much better MPG out of it, i was just wondering if any one else has tried it? or even tried the 100 octane and if they felt more power.

all i can say is this car surprises me every day i drive it. last night on my 90 mile drive back home i took down a bmw 3 series passing him doing about 120 on a banked on ramp, and was able to keep up with a C5 vet on the freeway. BTW the speed 3 on the freeway keeps up with the STi as my brother owns a 2007 one .

 

i wouldnt do that if i were you....

 

i live in Turkey and we have 95 97 98 100 octane. i get 95, anything above that might cause knocking. tried 100 octane just for fun. its maybe a little more responsive on high revs, but slightly, so no need for my small 1.6L engine.
but tests have been made and cars with turbo get more out of the higher octanes. if u've time & money just test them on a dyno. each time fully get rid of the previous fuel..