I just bought a used hardtop for my '04 C4S cab. While I am happy with my purchase, I discovered that PAG decided (starting with MY '04) to eliminate the necessary mounting hardware inside their cabriolets if purchased without the hardtop option. This means that I will have to buy and install parts for over $300 so that the rear locks of the hardtop can be fastened to my car. In addition, if the top is older than three years (like mine), new locks ($100/each) have to be installed. It is probably worth the extra 500 bucks, but '03 and older cabs didn't have to spend a dime....