There are a total of 4 cats, 2 (400cells) near the front section just after the headers, 2 (200 cells) just before the X-pipe portion and (2 resonators) just after the x-pipe section. Andrew@Active covered the rest. Here is a picture, the exhaust system starts on the right side of the picture. VVVVV
Your cheapest route would to replace the 400 cells with test pipes and install a tune. Here is a picture with the test pipes (left side). VVVVV
