hi. i am looking for a new set of dc headers since i scraped the hell out of the ones i have now. the downpipe is basically flat, so any performance gains i get from the larger diameter piping is lost. the weird thing is, ive been looking on ebay for the headers and they look different than the dc ones i have now. the downpipe has an extra flex pipe along with an o2 sensor hole. is this a new design? i remember when i installed my dc headers onto my car, it didnt include a flex pipe or o2sensor bung. i always hated that i had to keep this small piping from my factory exhaust for the o2sensor. does anyone know?