Recently installed a tarmac intake on my mk6 gti and noticed a slight whistle when decently accelerating. Had an apr stage 1 flash performed on Friday and now the whistle is massively prominent on acceleration. I've done some googling and intake harmonics comes up a lot with people divided as to what causes the issue and what the fix may be. A lot of people seem to upgrade the factory diverter valve to the rev d version as a fix. Anybody else had/have a whistling intake noise?