Personally I don't see it becoming worth much more than it currently is, as much as I love Q cars I just don't see them turning in to classics - the whole point of a Q car is that they're quiet and subdued looking which is the opposite of what makes a classic imho. Take previous Zs for example, hardly the most impressive performance wise, but the style has at least given them a cult following. On top of that just replacing the belts cost 50% of the cars value!