Legal advice needed

[Rahxephon]

I need a legal advice.

To make things short, my car was in an accident. I took my car to a body shop. After I got it back, I wasn't satisfied with the results. I posted the experiences I had with that auto body shop on various internet forums.

I took my car back there again. They said they would fix some of the issues for free, but made sure I'm aware they're not responsible for some of dissatisfactions I had from the previous results.

Now after I received my car back from them, they demand that I fully retract the things I posted on the forums. Otherwise, they implied they may sue me for defamation. I took some of my words back, but I don't feel comfortable deleting the whole threads. Many things I posted still hold true and I feel like customers should be as informed as possible. Because after I took my car to that body shop, many people told me I shouldn't have. To this day, I still regret not asking many people for advice before I took my car to that body shop.

What should I do? Any suggestions is greatly appreciated.

The detailed story is here: http://www.yarisworld.com/forums/showthread.php?t=7421