My 1966 Mustang has the original 200 inline 6 in totally stock setup. Is it worth putting HEADERS on a stock motor or not? Is the amount of power gains worth the BIG $$$ cost of the Headers + the 2" or 2 1/4" exhaust pipe + (Flowmasters mufler) + the labor for the installation all the way to the back of the car? Thanks in advance.