I'm running infinite baffle with a pair of IB15s. The Qtc comes out to right around .7 in my 15' trunk. I don't know why but I like the sound of the lower Q setups and venting my trunk to atmosphere makes this setup sound so much nicer. It was very nice to begin with but I feel like it sounds more natural when the trunk is vented. Right now I removed the factory trunk vents and put a screen over them. It helped. Pulling the weather stripping off the trunk helped even more. This is obviously only for experimenting, the weather stripping has to go back on. So I was thinking about cutting a larger hole than needed to the outside world and using AP mat in the hole to "tune" it to my liking. Is there any reason not to do this?