It can give the impression it makes a difference, as due to the butterly being larger, for every percentage the throttle is opened, the larger butterly will let in more air compared to the standard sized one - in reality it makes it snappier as it is letting in more air, but due to the throttle body not being a restriction, it doesn't give any noticable increase unless you are running big F/I.
You want to be looking at getting the upper and lower inlets matched, this has been proven to give good results