It looks like when passed no options, the trim method has three if statements and two string replaces. When passed even an empty option object, it has four if statements, the $.extend, and two string replaces. The $.extend is a function call so that has some overhead, plus all the code in $.extend itself (including loops) to copy all the default properties to the new options object.
For something as simple as a string trim, this seems too complex. Would there be a problem in having separate functions that implement the functionality rather than passing in a big options object? The method is going to be (relatively) slow if it has to check all those options each time it's called.