MPG? I know it's been beat to death, But

Hello, I just bought a 2007 Black R/T Nitro 4X4. I really do like it! The interior is just to simple for me, so I'm looking for some kind of dash kit for it to make it look more luxurious. Just not sure if I should go carbon fiber, bruch aluminum or wood grian!
But, my real problem is, my mpg's. I was looking at the Murano which gets 18-23, but my wife talked me into the Nitro.

Ok so far I've learned there are a few things out there that will help the mpg's!
There's the Air Intake (K&N 77 series) or (AEM Brute Force)
and then there's this Chip stage 1 & 2

I found where to buy the air intake, but haven't found anything on this chip

My question is will these products really work? My Nitro has plenty of power! I just want better gas mileage!!
Also I don't want to add exhaust. Maybe I'm getting old, but I did that to my Dodge Ram and I hated how loud it got. One thing I loved about the Nitro is it's so quite inside. Don't want to change that.

Can anyone point me in the right direction to better MPG'S

Thanks You, BTW - Great sight. Been looking at it since I've owned my Nitro
Rico