Unfortunately if you are trying to go slower and higher pitched at the same time, there's ALWAYS going to be distortion and bad sound quality. You can get high-quality plug-ins that keep the distortion to a minimal, but most of them are for Pro Tools or at least a software that can run VST plug-ins. If you happen to have one, try the one that Waves offers, or I hear that the one that Serato made works well.