[Plugin: List category posts] How to change link target

And by posting the question I figured the answer out myself.

Add the target=”_blank” code in CatListDisplayer (line 179):

private function get_post_title($single, $tag = null, $css_class = null){
				$info = '<a href="' . get_permalink($single->ID) .
					'" <em>target="_blank"</em> title="'. $single->post_title . '">' .
					$single->post_title . '</a>';
				return $this->assign_style($info, $tag, $css_class);
		}

Problem solved!
Good luck!