Personaly it sounds like an exhaust leak. Maybe at the header or the uppipe. A preturbo exhaust leak will kill any chances of boosting it also makes a whinning noise. It would also explain why your exhaust is louder. Crawl under there and check the tighteness of your exhaust bolts also check the O2 sensors and the preturbo sniffer to make sure everything is tight and there are no leaks.