If it's the main cat, a Magnaflow (Autosound) high flow cat, can be had on Ebay for around $30!! Go for it. My friend actually just bought one for his civic HB because it was extremely cheaper than OEM.

99 SVTC, T-Red, #652/2760-12.8.1998 Mother#@%@!* did I sound abstract? I hope it sounded more confusin than that!