Using Custom Taxonomy and Custom Fields Interchangeably

I am trying to create a form on a website of mine that lets you select a minimum price ($minprice), a maximum price ($maxprice), and a product category ($product_category) and then displays a list of products within that category ordered by rating.

I have created a custom post type:

Product

I am using the following custom taxonomies:

Price
Product Category
Rating

I found this code in the Codex, however it says that it is for custom fields and not custom taxonomies.

<?php
$meta_key1 = 'model';
$meta_key2 = 'year';
$meta_key3 = 'manufacturer';
$meta_key3_value = 'Ford';

$postids=$wpdb->get_col($wpdb->prepare("
SELECT      key3.post_id
FROM        $wpdb->postmeta key3
INNER JOIN  $wpdb->postmeta key1
            on key1.post_id = key3.post_id
            and key1.meta_key = %s
INNER JOIN  $wpdb->postmeta key2
            on key2.post_id = key3.post_id
            and key2.meta_key = %s
WHERE       key3.meta_key = %s
            and key3.meta_value = %s
ORDER BY    key1.meta_value, key2.meta_value",$meta_key1, $meta_key2, $meta_key3, $meta_key3_value)); 

if ($postids) {
  echo 'List of ' . $meta_key3_value . '(s), sorted by ' . $meta_key1 . ', ' . $meta_key2;
  foreach ($postids as $id) {
    $post=get_post(intval($id));
    setup_postdata($post);?>
    <p><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></p>
    <?php
  }
}
?>

Does the fact that I am using a custom post type with custom taxonomies instead of a regular post with custom fields affect the way that I would have to use this code?

Also, can anyone add a little code that would restrict results to only products within the price range set by the form?