I just installed an S&B intake along with the SC 3865 91 Performance tune. I have heard that you should get a tuner with the CAI to really feel the difference. The S&B sucks in 38% more air than the stock air box. You need the tuner to make the adjustments for the extra air. Let me tell you...the combination of the intake, tune and 14" magnaflow really woke up the Hemi!
I am glad I did it. I took a trip yesterday to see if there were any mileage gains and this is what I found. 130km round trip to town I usually average 14.5 to 14.8 L/100km. Yesterday I averaged 13.3 to 13.6 L/100km. So I am definitely seeing an improvement in mileage.
Here's a pic of the S&B