well i got my sweet x2 and i could notice a pretty big difference. as soon as i burn out the 87 octane i am gonna try out the 92 program. i really noticed that wheni shift that the engine really shut down as far as throttle. wheni use to shift the rpms would kinda dive slowly when i pushed the clutch but now its just like bam! confusing to explain. but anyways i really like the x2 and recommend it to anyone thats wants some umph. can't wait to see what the 92 does!