Catalytic Converter Failing

Took my car to a shop today after I'd been experiencing a "tinny clunking" sounding rattle. I was worried it might be my catalytic converter and after couple of bumps on the exhaust system while on the lift, the tech thought this was indeed the case. Replacing the catalytic converter could be a $1500+ job from what I hear if replaced by toyota.

Anyone else had problems with the cat? I do not live in California and will not be needing to do an emissions test at all. Will the prius allow for a custom system or are there so many sensors that my car will go nuts? Car is a 2010 prius with about 130k miles. Again, I'm just most worried about the car functioning safely rather than worrying about my MPG. Really don't want to spend $1500+ on a new system when I could have my friend's shop fab me an awesome system for probably <$600 if my car will still work

 

Thanks all. Yes I was just a bit concerned though that the GENIII Prius might be more of a trouble maker when it comes to the exhaust system. Heard something about system recirculates exhaust gasses? Also, would consider going with a high flow cat but I don't want the whole system to freak out on me just because emissions at the sensor are a little higher than its used to

 

Thanks JimboPalmer! This says 2004-2009 though, I'm a 2010...

 

I'd rather go for a performance unit that at least makes it sound good and looks good (obviously no performance to be had from the Prius)

 

Haha bisco, if I could do something that spit flames I would. Heck, the McLaren P1 (which I got to experience last week, woohoo!) made hybrids cool by blasting around the F1 Circuit in Abu Dhabi with a blue flame shooting out its rear. Bout time the Prius (ahem, the McLaren P1's inspiration!!!)) did the same!

Any input though if by going custom I'd be putting my engine at risk, please feel free to chime in. Even if I get a CEL code, will the engine still work fine and I just have to deal with the light on my dash?

 

Do you mean fail emissions from a state testing standpoint or do mean fail emissions as in my ECU will give me problems and the car won't operate?
I'm ok with a simple light on my dash as as long as it isn't doing actual damage to the engine components. My car is exempt from state testing, plus even if I did have to test for some reason I can simply bolt the old system back on for that.