a 3.325 from a 3.4 is going to barely make a difference. its not worth buying that pulley when you can just increase timing instead.

now, if you were dropping to a 3.2 or lower pulley from a 3.4, id say go for it.

otherwise, with headers you should be able to run a 3.4 if you get a tune. with 110 octane you can run a lot lower pulley, but are you really going to run that all the time?