i think the problem is consistency....i was mapped for 95 and a FULL bottle of lucas when e5 first came out the car ran better on e5 alone ..but various fill ups now and again the car felt sluggish..to say its the same as 95 is wrong imo..i was mapped recently on e5 alone and no timing was taken out and made more boost than 95 plus full bottle of booster..i know the b4 runs higher compression and doesnt compare to the impreza..i wouldnt say its 99 but its deffo better than 95..depends where you buy it i reckon..i have noticed some garages have E5 on the pumps and some just have "now with 5% renewable bio-ethanol"..i know it amounts to the same thing but maybe maxol can answer a few queries for us...