For a pre-L Pantera, these from the same seller look almost just like the ones
from PI, except they're $49 instead of $150 ($140 member price):
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=180509063211
PI's mufflers:
http://www.pim.net/mpage.html (bottom of the page)