Obviously, if you find this too expensive, you must be one of those poor commoners who is pretending to have enough to own an NSX.
http://www.scienceofspeed.com/products/exhaust_airflow_products/NSX/Fujitsubo/headers/
http://www.scienceofspeed.com/products/exhaust_airflow_products/NSX/Fujitsubo/headers/