That's a big negatory. CD6 has been abandoned and only left for Explorer/Aviator. Mustang soldiers on staying on the current platform next go around. D5 is the new Fox body.
Blame your local politicians for the "blend" situation. With each state requiring different blends for different seasons throughout the year and for supposed environmental reasons, refinery capacity is strecthed thin leaving us, the good old American consumer, getting the shaft. It should be simple, pick the best blend for everyone and use that one nationwide. The capacity issue has much less to do with the octane levels than this "blend" issue.