i've been using bp ultimate for about 4 months - getting about 240kms per tank
switched to v-power racing last week - got almost 300km out of her.
BUT - on cold starts, I noticed yesterday that when i'm idling, i can hear the engine stuttering every few seconds. once the engine's warmed up, i couldn't hear it anymore. it didn't really drop in revs that much, and didn't stall. was quite disconcerting tho
it might but completely unrelated to the switch in fuel, but it's a big coincidence
i'll switch back to bp ultimate this week and see what happens