Mike,
I am well familiar with Exc. headers. If your still using the system they made up for the "cats", your right, Your headers are killing you engine! Choke, choke, cough, cough!
You need to find a stock set of CR's headers- (they will bolt in place), my guess is you will gain 25/35 useable HP!
Then modify the sidepipes and you'll think you swapped in a BB engine!
DV