Hooking to manifold vacuum just masks a problem but is a quick fix for people who lack the now how (like the guy at FBO) to get their idle timing to a place where it needs to be after performance changes.

Vacuum advance was designed to pull extra timing on at highway cruise to give better gas mileage. If your using it improperly at idle you are not making proper use of it cruise.

So going to manifold vacuum at idle you will be giving up some of the performance a motor could offer and will also not be getting all the gas mileage available.

To most on hear the all the power a motor can deliver is not a Goal so my question is why the upgrades???