I have the JLT CAI and can tell you that it actually helped my mpg quite a bit. At least 3-4 mpg I'd say. More power AND better gas mileage, what have you got to lose, eh? Other than around $600.

It's worth it.
I've heard too that the plastic tube is better with heat, but I've also heard that the air in the tube doesn't stay in there long enough for it to really matter much. JLT and C&L are both great, It think its pretty much down to the look and price you want.
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Black 07 V6 Pony Package, JLT CAI, Bamachips Tunes, Eibach Pro Kit lowering springs, Magnaflow Dual Exhaust, 17" American Racing Rogue Wheels, BF Goodrich g-Force T/A Tires, Roush Hood Scoop, Roush Quarter Window Louvers, Sequential Tail Lights.