Hi all, Just got my 2010 S3 Sportback stage 1 Shark mapped by Brodster on Saturday. Firstly, what a map, very smooth in delivery and the mid-range torque increase along with how long the boost holds now is quite something, really impressed, thanks again Mark. One little issue though. When really getting the power down, especially in 2nd, 3rd and 4th as soon as the car comes on boost I'm getting quite a high pitched chirpy squeal from the engine bay, pretty noticeable. It's not turbo whistle and it's only when on boost so not the compressor stall noise that I see a lot of people query. Sounds a little like a split recirc valve diaphragm I had on my old stage 3 Astra VXR but what I've read my March 2010 car should have come fitted with the revision D recirc valve which does not have a diaphragm? I've not checked yet will do later in the week. Just wondered if anyone had noticed the same thing or any other ideas as to what it might be?