The Accessories & Similar products add-on will help you set up an automatic selection of appropriate products - accessories and similars, based on their cost and features. You can customize selection rules for categories (including their subcategories) and separate products, add manually selected favorite similars or accessories, hide out-of-stock or unsuitable by their cost products, use different sorting methods within one tab.
Alternative Checkout Complete Page add-on makes user's navigation easier, replacing checkout complete page with a new, more detailed and convenient one. All the needed info is gathered in one place now, and selected shipping address is shown at zoomable Google map.