High pitched whistle/stereo security code

[Dr0]

my issue at hand is that when i get to about 2500-3000 rpm sometimes i get a high pitched whistle, im a bit confused as to what it could be. I dont know if this would be related but i have a nasty boost leak in the stock intercooler hoses where they hook up to the turbo/intercooler.

and i feel really dumb because i disconnected the battery tonight to clean the terminals and now i need to enter the head unit security code... which i dont have... and my kenwood booklet is in spanish and french?!?!? WTF lol this is bulls***

any advice would be awsome!