Leave the main cat alone, gut the pre-cats and port out the primaries of the front manifold (you'll see what I mean when you have the manifold off- it could use some help!) and put it all back together. Total cost: Less than $20 for a good boost in power and a bit louder exhaust. It probably will rasp a bit when first started, but that goes away after a few minutes. A how-to on the manifolds is somewhere in the Performance forums..I would highly suggest removing the front manifold (a real PITA!) to do the porting as those primaries are very choked down with extra gunk from where the flange is welded to the primaries...
Even when you do this you still won't be as fast as me ...
Alex
