Greetings John, the Stayfast or Haartzcloth is absolutely worth the extra money if you're going to keep your car and if not probably worth it if you sell it because it presents so much better. My first replacement was Cabrio, it ripped the first year and it was downhill from there...lol One of mine has the Robbins top ad it is an excellent top. You might try eBay, the convertible top guys make a good top. If you Facebook you might try 1991-1994 Mercury Capri Owners Group, a sister to teamcapri.com and 1991-1994 Mercury Capri Scavengers Group for parts.
Good luck and glad you're onboard.