Currently using a CP-E intake. Putting a felt like material around the outside of the box helps a bit. During winter, I put a big rubber plug in the lower cold-air intake pipe. Both reduce the noise about 50%. I hate the sound still, but I try to ignore it. I also have subconsciously changed my driving style to either keep the boost above or below the magic psi / flow rate that the noise is made.
I learned the hard way not to put felt on the inside of the airbox without copious amounts of glue. The material got sucked up against the filter and pretty much choked off all air flow. Didn't help the noise at all anyways.
I had an email out to pumaspeed a while back about their updated inlet adapter and they told me it would make no difference to the noise.