Don't sing the praises of the '06 factory air box or any others for that matter. It's 11"+ of restriction on the flow bench manometer at full throttle demand. The good CAI's cut that down by almost 50%.
We applied 250 degree heaters below the tubes while dyno testing with our normal 28,000 CFM fans. This ideally simulates what occurs during high performance driving. If a dyno shop uses a small blower while testing your car, consider it not credible in terms of actual performance gains. If you close the hood and test without a fan of this capability, open the hood. The results are more accurate.
Getting back to the heat soak dilemma, the velocity of the intake charge at full throttle demand realized almost no increase with the heaters applied to single and dual intake aluminum tubes. It's not worth the discussion about heat soak. It's a non-factor during high performance operation.
Apexi is junk. A good intake makes much more than 5 on a 350z. The bad ones make much less. A panel filter makes zero in repeated tests. It drops the restriction on the flow bench by 3 tenths and it's much worse wwith regard to stopping dirt.
Air filters with internal cone designs or those that sacrifice internal space make less power as a rule. The open end cap does not work well.