I still don't think the design of have an intake with no box around it and having it suck in the hot, engine compartment air, is going to give you any performance gain and make actually hinder it. I think the stock air box would be a better design than an intake that sucks in hot air. If you can't find a way to box it off so it can be fed cold air, I would ditch it and get another air intake---a "true" cold air intake---like those offered by Volant, Injen, AEM, etc.
Last night I spent reading a thread on CAI's at ClubTitan's forums, which I'll link to below. A member had a Titan with some substantial mods to it and access to a buddy's dyno and also took the vehicle to the track to get some real #'s. Now, I know Pathfinders to Titans are apples and oranges to some extent, and that the Titan had mods to it also may have different results compared to a bone stock Titan, but the results were interesting and he really put a lot of time to give a fair and impartial comparison of multiple cold air intake systems, including a stock air box with the so-called "Titan mod." His testing pretty much found, more or less, that most of the aftermarket systems were pretty close as far as gains (all of them were sealed off from the hot air of the engine compartment) and the biggest differences were in the level of noise. It seems the best system was from S&B Intake systems, which, unfortunately, only make one for the V8 Pathfinder, not the V6. Volant and Injen were pretty neck and neck for second place, with the Volant being a little nosier, but the Injen gave him a slight benefit in track time over the Volant. Here's the thread:
http://www.clubtitan.org/forums/showthread.php?t=13697