Jetting Recomendations

Hey guys whats up? Im new to the forums :icon_biggrin: . I recently got a hold of a modded 08 YFZ 450 SE but Im not sure just how modded it is. Its pretty fast but not as fast as it should be for the mods it has :icon_frown: (as Im told). I was given the suggestion it might be my driving thats the culprit but I got an experienced friend of mine to run it and the results were right about the same. I do know it has yoshi full exaust (header and all), a k&n filter with precharger and the airbox lid off. I would assume with those mods that it is also jetted (I believe the jet kit might be gytr) but I dont think it was jetted right. It straight out dies if i stab the throttle from idle everytime, rolling or not. Im gonna re-jet and I spent quite some time lookin at the FAQs and stickys it but I was just wondering what the experts here would recommend on jets and needle settings for mine? My elevation is 2,2824 ft. Sorry for the rambling and thanks in advance for any suggestions. If you guys need any other info just let me know and Ill do my best to get it.