My question is hopefully a simple one. I am looking to get a true flow kit or an airraid jr. kit.
How much noise will increase over the stock tube? my reason for asking is two fold. First is that I'm trying to do this behind my wifes back and don't want her asking about the noise and Second will I notice a gain in gas milege?
I don't know about your Expy, but my Explorer pulls in air from around the R/H headlight assembly; can't get much colder than that, especially if you have an exposed filter under the hood. Metal tubes also transfer engine heat to the intake air faster than rubber. MPG increase will be tiny to non-existent. She'll notice an increase in noise if she uses WOT a lot.
Both the Airaid Jr and truflow should be vacuum formed plastic tubes, so convection should still be at a minimum. However chrome tubes reflect plenty of heat, so I haven't heard/read a decent argument for either material.
If your Jr kit is just the MIT, I don't think you'll notice any change in noise since the filter is still baffled. Between the two, I'd pick the truflow, it comes with more parts. I doubt you'll notice any change in mileage, maybe a couple of miles per fill up, but a full MPG would be a little much to expect.