So.... Ive read way too much and still know nothing, i just bought an 05 z4 2.5. It has 75k miles on it and im wondering if at this point its normal for it to whistle in neutral and while driving under light pressure. Like 2k rpm anything before or after no noise. I bought a new intake hose and disa valve already havent put them on as my disa is good but hopefully the whistle stops when i replace the hose. If you have any info let me know.