what performance/aftermarket header pipe actually increases flow.... some of them are just chrome etc... i want one that actually flows better than stock... my 350x has a dg pipe on it but i dont know if the header pipe's is stock?? how can i tell? mine may just be a slip on.. but it is loud as @#$% so im sure its gutted... it runs awesome but i have been thinkin about the header pipe to put in front of that dg. make it flow a little better that is if my header is stock