I will tell you what I think about it when you can tell me more about it. the pulley crank " the sport kind " Be lighter and smaller diameter, which increase the speed of the engine, which increases the number of horses it's give minimum 8 horse power ... Therefore, I wan't By the way i buy 6 spark plugs for avalon ... i put it in aurion engine ... it's work very nice ... i think Increased 4-7 hp So you've had it on a dyno? Got a print out for evidence of this power increase? i try a drag race with my friend before and after install the sparg plugs from 0-200 km ... i was first 1 and the defrient between us nerly 25 meter ... before install i was in front of hem by 2 meter