tailpipe wont come off 91 civic -- tuffy's gouging

Hi guys,

Problem in short:
91 civic STD 3DR-hatchback 1.5L MT
The tailpipe is badly rusted on my car, no noises yet, but state inspector
reccomended replacing. But is it welded on (tuffy's muffler job)? Or is it just
rusted tight? I tried for an hour, alternating WD-40 ,hammering, pulling, but it
wont come off and I was afraid of damaging the muffler. My hammer even broke its
wooden handle, but the pipe is still attached. I took the clamp off but do they
punch it to the muffler in some way? I have a new pipe of the same shape as the
old one ready to go in. The muffler is new.
Any tips to get it off is appreciated. And also how should I put the new one in?
any sealing required?

Detail:

State inspection failed on exhaust. Muffler bad. Was installed last year by
Tuffy's. I think they use the cheapest possible type that lasts for only an
year. Anyway I took it back for lifetime warranty thinking thats no cost to me.
They call me later with an estimate of $80 . I say why? And they say yea muffler
is free, but the tailpipe is not included, and somehow added some shit together
to make it $80 FOR JUST THE TAILPIPE. (including a price of $25 on the
tailpipe) Can you imagine? I checked my last bill from an year ago when they put
in the muffler and the tailpipe was listed as costing $13. I asked him about
that and he said prices rise. I said they rise yes, but do they double every
year? Ass.
I said ok dont put the tailpipe in, leave the old one on, I dont want to pay you
anything. I will put it in myself. And he reluctantly agreed. Car runs fine on
old tailpipe, without any wierd noises too.
I bought a new tailpipe from Advance Auto for $4.77. But when I tried to take
out my old tailpipe, it wont come out. I have it somewhat loose now, but its
still stuck. Looks like the mechanic welded it on or something to give me a hard
time. Anyways I dont have a torch or anything to cut it or weld, and I want to
avoid cutting it anway.
Also assuming that I put the new one in, how should I do it? No auto repair book
talks about this job at all, and I am clueless about how to attach the pipe
securely. I mean I assume the U clamp is not going to be good enough by itself?
Leakage?

Thanks a lot!
Ak

 

.. I took the clamp off but do they

And both the tailpipe and the muffler exit pipe are now deformed, securing
them together.

itself?

See above. Looks pretty darn effective to me.

 

If you successfully got the clamp off and it refuses to
budge, it's rusted on. At this point any muffler shop would
tell you this and then try to sell you a muffler too. i had a
beater were i cut off the rusted portion and cut the new piece
too, I "sleeved" the 2 pieces with another and 2 clamps.