Extractors are like exhaust manifold but designed to up the performance of the engine i.e let it breath better than the stock manifold.They are what the guys here call a BANANA BRANCH it should change the sound of your engine but I agree with the guy at Carb Kings adding this stuff to a stock motor wont really do much for performance also if you are having problems with your motor and it's not up to scratch I think adding a branch (extractors) would be a waste.I say rebuild your motor with a mild cam,skimmed head and then upgrade your carb to 32\36 Weber and 4-1 extractors and you should have a Datto that wont be the fastest but would still be a treat to drive.

Only my two cents worth