tune-up and muffler change

[Minven Wang <mwang@stern.nyu.edu>]

Hi.  I'm going to have a tune up and muffler change on my trouble-ridden 5kcs.
The only local Audi specialist, Bruno's Quattro Center, is changing an arm
and leg.  Since these are rountine jobs, can I trust a non-Audi specialist
to do these jobs.  Sears is advertising a good price for mufflers, does
my '86 5000cs require special mufflers (both the main silencer and the front
silencer).

BTW, there always some waters dripping down the exhaust.  When I have the 
Bruno's fixing the car, the mechanics said it's no problem.  Whenever I
turned the engine on, (regardless of the weather, and A/C is off), it always
have some clear lequid dripping down.  I wonder where these waters coming from.
That may be the reason the muffler is very rusty.  Any suggestions?

Minven
Audi '86 5000cs (about 100k miles)