Для поиска советую яндекс поиск для интернет магазинов

Например multisearch.io/. Не пробовал, но возможность интересная. Во всяком случае, там реализованно много фишек для более лучшего фильтра. Например исправление ошибок и опечаток и исправление раскладки.

И не включать фильтры в поставку.

Для MiniShop3 планируется сделать фильтры встреенные в него

<?php
$mess = array();
$thrs = array();
$table_mess = $modx->getOption('table_prefix').'ec_messages';
$table_threads = $modx->getOption('table_prefix').'ec_threads';

$sql = "SELECT * FROM {$table_threads}";
$q = $modx->prepare($sql);
$q->execute();
$threads = $q->fetchAll(PDO::FETCH_ASSOC);
foreach($threads as $thread){
    $thrs[$thread['resource']] = $thread['id'];
}

$ids = $modx->getChildIds(5,10,array('context' => 'web'));
foreach ($ids as $id){
    $tid = $thrs[$id];
    $sql = "SELECT * FROM {$table_mess} WHERE `thread` = {$tid}";
    $q = $modx->prepare($sql);
    $q->execute();
    $messages = $q->fetchAll(PDO::FETCH_ASSOC);
    foreach ($messages as $message) {
       	$mess[] = $message['id'];
    }
}
return implode(',', $mess);

[[#[[+thread_resource]].pagetitle]]
[[#[[+thread_resource]].logo]]

boolean setTVValue (str|integer $tv_name OR ID of TV, string $value)

[[#[[+thread]].pagetitle]]
[[#[[+thread]].logo]]

$ids = $modx->getChildIds(5,10,array('context' => 'web'));

$ids = $modx->getChildIds(5,10,array('context' => 'web'));
$mess = array();
$table_mess = $modx->getOption('table_prefix').'ec_messages';
foreach ($ids as $id) {
    $sql = "SELECT * FROM {$table_mess} WHERE `thread` = {$id}";
    $q = $modx->prepare($sql);
    $q->execute();
    $messages = $q->fetchAll(PDO::FETCH_ASSOC);
    foreach ($messages as $message) {
       	$mess[] = $message['id'];
    }
}
return implode(',', $mess);

[[!pdoPage?
    &element=`ecMessages`
    &threads=`*`
    &messages=`[[!getMessagesIds]]`
    ......
]]

[[#[[+thread]].pagetitle]]
[[#[[+thread]].logo]]

<?php
$filterz = '';
if(isset($_GET['types'])) $filterz = $filterz.'types=='.$_GET['types'].',';
if(isset($_GET['config'])) $filterz = $filterz.'config=='.$_GET['config'].',';
if(isset($_GET['style'])) $filterz = $filterz.'style=='.$_GET['style'].',';
if(isset($_GET['fasad'])) $filterz = $filterz.'fasad=='.$_GET['fasad'].',';

if($filterz !=='') $filterz = substr($filterz,0,-1);

return $filterz;

[pdoTools] Error 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '"`TVtypes`.`value` LIKE '1\"' AND  ( `msProduct`.`parent` IN (2,24,5,6,7,8,9,10,' at line 1

[[!msProducts? &tpl=`tovartplCat` &limit=`64` &parents=`2` &tvFilters=`[[!where]]` &includeTVs=`types,config,style,fasad` ]]

<?php
$filterz = '';
if(isset($_GET['types'])) $filterz['types'] = $_GET['types'];
if(isset($_GET['config'])) $filterz['config'] = $_GET['config'];
if(isset($_GET['style'])) $filterz['style'] = $_GET['style'];
if(isset($_GET['fasad'])) $filterz['fasad'] = $_GET['fasad'];
if($filterz !=='') $filterz = substr($filterz,0,-1);

//if(!empty($filterz)) {$where = json_encode($filterz);} else {$where = '';}

return $filterz;