AEM intake
 

Just installed an AEM intake on my 2004 MSM, now at about 2-7 inch vacuum sounds like a frog or a fart?
Is this the issue with the BPV or just due to hearing it louder with a more open intake?

The latter - the OEM intake muffles a LOT of the noise and the open-air CAI allows you to suck in much more fresh air.

I found that the addition of the FM MSM 2.5" exhaust quietened it down to some extent which I assume was due to improved airflow or that I'd just gotten desensitised to the coughing/farting noises.