Oxy Sensor & exhaust replacement

[gt6493c@prism.gatech.edu (Eric J. Fluhr, gt6493c)]

Hey gang,
I was gone for the summer (back home for summer break), but came back to
a ton of messages.  It looks like you all have been busy.
Well, anyway I have a few questions.  For one, my '85 Coupe GT has been
getting poor gas mileage lately, and I decided to replace the oxygen
sensor in case it hadn't been replaced before (I bought it at 63K, now at
96K).  Does anyone know of an easy method to take out/put in the sensor?
My father had seen a special socket (down in So. FL) with a cutout for the
wire to come through, but I don't know where to get one like that here in
Atlanta.  Any other ways?  I only have a small set of tools here at school,
but I can afford to but a tool or two.  I thought of cutting off the original
wire and using a deep well socket, but the sensor is too long for that.

Also, I have pretty much let my muffler system go as long as possible.  I
was hoping to get a Leistritz Sport Sound replacement, but they don't make
one for the Coupe (or any Audi, as far as I could find out).  The only place
I could find a performance muffler was Eurorace for $160.  The price was
great, but I am a little wary of it.  Still, I went ahead and ordered it and
it should get here this week.  Does anyone have any experience with this
company, or know anything about this muffler?  One thing I did like was that
they seemed pretty knowledgeable about the Coupe/4000.  

Thanks,
Eric