As a rule, when using regular expressions in Xbench, I would suggest searching first a character or a string that does not contain regex syntax.
For instance, in ^[^\(]*\)|\([^\)]*\(|\)[^\(]*\)|\([^\)]*$, you start searching any character different from (, that does appear 0 or more times at the beginning of the string.
This search takes more than 70 seconds in a project with more than 100,000 segments in Xbench 3.0.
If you use the following one, it just takes 12 second:
"\)" "^[^\(]*\)|\([^\)]*\(|\)[^\(]*\)|\([^\)]*$"
Press Ctrl+P to run a Powersearch.