I currently have the JLT CAI on my 2005 Mustang GT. I had loaned to me a Steeda CAI and C&L Racer for a test I never did. I personally like the C&L racer.
That said, I am not sure a CAI is a great investment for these cars. I haven't had my car at the track with the CAI installed on it. However when all I had was a tune( SCT X-Cal 2 ) and stock airbox, I was running slightly faster E.T.s and similar MPH to those that had a CAI and tune. The tune is a bigger piece of the equation than the CAI is. This spring when I get to the track, I do intend to see how the car does with the CAI compared to the stock airbox.