Hide the "Membership Level" description and pricing box at Membership Checkout and replace with our own box with radio-selection for multiple level display.

maybe_add_choose_level_section.php

<?php
/**
 * Hide the PMPro pricing box at checkout and replace with our own.
 *
 * Requires Paid Memberships Pro v1.9.5.6+ and the Sitewide Sales Add On v1.0+
 *
 * Add this code below to your PMPro Customizations Plugin - https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function maybe_add_choose_level_section( $include_pricing_fields ) {
    global $wpdb, $pmpro_level;

    // Make sure Sitewide Sales Add On is active.
    if( ! class_exists( 'PMPro_Sitewide_Sales\includes\classes\PMPro_SWS_Settings' ) ) {
        return $include_pricing_fields;
    }

    // Hide the default pricing box.
    if( PMPro_Sitewide_Sales\includes\classes\PMPro_SWS_Settings::is_active_sitewide_sale_landing_page() ) {
        $include_pricing_fields = false;
    }

    // Show our own radio select and info.
    ?>
    <div id="pmpro_levels_select" class="pmpro_checkout">
        <h3><span class="pmpro_checkout-h3-name">Select a Level</span></h3>
        <div class="pmpro_checkout-fields">
            <div style="cursor: pointer;" onclick="jQuery('#levelradio1').prop('checked', true);">
                <h2>
                    <input id="levelradio1" type="radio" name="level" value="1" <?php checked( $pmpro_level->id, 1); ?> />
                    <strong>Level 1 Name:</strong> <strike class="muted">$97</strike> $47
                </h2>
                <p>About the level 1 membership.</p>
            </div>
            <div style="cursor: pointer;" onclick="jQuery('#levelradio2').prop('checked', true);">
                <h2>
                    <input id="levelradio2" type="radio" name="level" value="2" <?php checked( $pmpro_level->id, 2); ?> />
                    <strong>Level 2 Name:</strong> <strike class="muted">$197</strike> $97
                </h2>
                <p>About the level 2 membership.</p>
            </div>
        </div>
    </div>
    <?php

    return $include_pricing_fields;
}
add_filter( 'pmpro_include_pricing_fields', 'maybe_add_choose_level_section' );

This gist is not compatible with the Sitewide Sales plugin and will need to be updated to work with that plugin. You can use a modified version of this recipe instead: https://gist.github.com/kimcoleman/0146529d87c2950e43b23c9f4d2dfa71