I just bought my first 2dr (title), it came with very high miles but i DONT CARE!!!!!!!!

Well, my catalytic convertor sounds like a damn exhaust.....Which catalytic convertor should i buy to replace it?

Would you guys recommend this one?http://cgi.ebay.com/ebaymotors/90-91...ayphotohosting

Or should i go to the junk yard a buy a used oem one??
Please help me!! Im tired of my car sounding faster then it usually does