[urq] Catalytic Converters

[Andrew B]

I'm taking a look at a UrQ this weekend that has a straight-back 2.5"
exhaust with no cat.  I'm not sure I could pass inspection in MA
without a cat, even though pre-84 cars are exempt from emissions.  I
see a lot of the universal cats do not come with flanges.  Does
anybody have any suggestions on how I could install one  with minimal
cost/complexity?  Does anybody have any good resources for a high-flow
cat?  Have any of you ever built your own exhaust systems?

I suppose I could take it to an exhaust shop and say "here" but I'd
rather do it myself, if possible.

-Andrew