Honda Element catalytic converter

My honda element’s catalytic converter got sawed off in the middle of the night, ouch! Because the Element is a low emissions vehicle, I was wondering if there was something special in the original catalytic converter or whether I could replace it with a generic part. The local exhaust mechanic says he can drill an extra hole in the generic part to make space for two oxygen sensors which is normal in the Element. How would this solution compare to the original part?