You have too much vacuum... the stock type PVCs can't handle it.. LOL
I have a 03 Ram with a big cam and my power brakes work fine. They sometimes feel funny in parking lots but I don't feel any differences other than that. 8 inches of vacuum most of the time at idle. You need a bigger cam... lol
If it was me I would go ahead and buy the M/E Wagner and adjust it to the vacuum needs. I bet the whistle will be gone because of the different type valving.
