Rgoose, I am not avoiding your recurring question on purpose but instead just have to explain I have a lack of experience with the J's Racing intake. The Carbon Fiber whore will love it. I personally don't care about throttle response and have a hang up about cold air intakes being btter than any short rams.

Of the 4 intakes I might consider it would go like this

Mugen
Icebox
AEM
J's

THis isn't to say it doesn't work or that anyone made a poor choice but this is how I would do it if money were no object. The Icebox gives good power/power curve and is quiet and sedate looking. When discussing an intake for a lightly modded R you won't see a huge variance between any and none of them make big power over the stock air box.

Pick what you like, I like the Icebox.