Hi Barry,
I use my GT40 mostly for trips to the local plumbing store for supplies....or sometimes to get milk for the (four) kids...and occasionally a dinner date with my wife on the rare occasion a) we can convince someone (dumb enough) to babysit four unruly kids, and b) my wife has forgotten how loud it is, and how uncomfortable the seats are, since the last time she was in it.
Never used it for a track event (not allowed in the local vintage racing, transaxle too weak for real track time), nor a weekend trip (too loud and uncomfortable), nor a long cross country drive (again, not comfortable).
That said, I'm planning on doing a desert drive this coming Summer. We'll see how it goes.