I have been communicating with Cravenspeed about a short antenna for the convertibles. They are sending me a prototype to try. I will keep y'all updated.
Great! I have the old one from my 2012 on my car now, but the base of it is a bit larger than the base mounted to the car, leaving a slight gap. I filled that with a rubber washer, works, but not perfect. I would go for a new one today if it were available.