If i were in a clan, can i quit and join another?

Yes.

ah thanks!

I also had another question.
Why does other thread had "search this thread" while others doesnt?

It's toriprime exclusive

i know it is and only them can use it. What i mean is other thread has that "tab" or what you call that, and others dont.. Why?

There is a "Search This Thread" thing at the top of this thread for me.

yah. there is. But if you go to other sections such as the market, there's none