yes definately the crank pulley gets you way more power...but there is a bigger risk at stake with eninge life. quite a few people have encountered engine problems with using UR crank pulleys...do a search in ecelica.com and newcelica.org...the the result can be pretty horrifying.
someone told me that if you add just the AEM
pulley you will feel almost nothing. but if you have more mods thrn you'll get the most out of it. kinda like a flywheel...
i am quite happy with my AEM
, plus they sell them here at the store which is a plus!!