i have two cool air intake systems, one is a K&N which has a plastic connection tot eh intake manifold, the other is soem other one that came with the car i got when my other one was crashed, it ahs all metal up to the intake manifld, which is better for my car which will give me more power, eventhough im sure it is not that much for a difference.

 

I think that its a question of which one looks better to you...All the major ones flow the same...So its a matter of preference. I like the plastic because it looks more factory. I have an LPE cold air induction and its been there since 1995. The metal SLP is also a popular choice here as well as the K&N...

You could argue that the metal would retain heat and would heat the intake charge, but I don't think that the air is in the tube long enough to get heated...Go with what fits well and looks good to you!
--Alan