E28 Exhaust Options

[Doinitin3D@xxxxxxx]

I have just acquired a 5spd '85 535i (which has almost enabled me to forgive
my father for selling his '83 533i when I was 17).  Regardless, there is a
leak in the converter, and idle is a bit on the rough side.  Proper and
consistant rpm, but rough.  There are three ties from the cat to various
places - will the leaking converter throw other components off-kilter?  (I
haven't even done a simple tune-up yet, so I suppose I should save my
questions, but the exhaust needs attention.)  Any suggestions from experienced
folk would be greatly appreciated.  

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