Help! Failed emissions with cat-back exhaust
 

Hi all, I bought an 05 RX-8 a few weeks ago and finally got the title in the mail from the seller's bank. So I went to the DMV to get the title transferred and found out I need to get my emissions done. No biggie there.

The check engine light is on because of the cat-back exhaust the previous owners installed. After some research and looking at other threads on this forum it appears to be semi-normal, especially the fact that it runs a little rich.

I got two fail codes on the emissions test:
P0420: Catalyst System Efficiency Below Threshold (Bank 1)
P0704: Clutch Switch Input Circuit Malfunction

Hopefully somebody can help me out here? I'm going to contact the seller and ask how they passed emissions testing, but I'd appreciate some input from others as well on what I might be able to do.