eaxmple of ajax_wpqsf_reoutput filter

add_filter('ajax_wpqsf_reoutput', 'customize_output', '', 2);
function customize_output($results , $args){
// The Query
$query = new WP_Query( $args );
ob_start(); $results ='';
// The Loop
if ( $query->have_posts() ) {
while ( $query->have_posts() ) {
$query->the_post();
echo '<li><a href="'.get_permalink().'" rel="nofollow">'.get_the_title().'</a></li>';//here where you customize the result content
}
} else {
echo 'no post found';
}
/* Restore original Post Data */
wp_reset_postdata();}

$results = ob_get_clean();
return $results;
}