I also wrote a history of the kit for my Vintage Workbench column in Model Cars Magazine. The annual kits all had optional drag slicks that were taller than the tires in the latter kits. The 65-67 annuals had a different front frame clip that allowed working suspension with springs. All annual kits had full stock exhaust system as well. The 65-67 also has the year correct seats and interior door panels. Only the 66 and 67 annual kits had stock wheels. When the Streaker came out in 1974, the original front chassis clip (with steerable wheels only) was returned, along with the 1964 interior tub. (I'm guessing the other insert was modified for the Cosma Ray. The stock exhaust was removed, but other than the removal of the brake drums/disks, I don't think there were any other changes to the chassis and suspension.