I modified my stock air box with a 3" air tube from the bottom, and hollowed out my inner fender a little with a grinder. I was following older threads about the stock box being better because of the engine heat. I was of the opinion that it was.
I installed an upper blower pulley a couple of days ago and now it seems the boost gauge rises faster with the open 12" filter than the modified stock box. I also keep more boost at the shift with the open filter than the modified stock box. Is this better? Has anyone else experienced this?

 

Sounds like with your testing, open filter is the way to go...