There was a great thread about car topping with some neat drawings by mmiller at http://www.hobiecat.com/community/viewtopic.php?t=1100
I would consider the 16 if there are two of you. If you are beginning and don't have a "guide" the 16 can be intimidating though. Some newer models are more "user friendly" especially to beginning sailors. At the top of this page go to >Products> Hobie Sailing> View All Models and check out the Bravo and the Wave.
The Bravo is a really great little boat that sails two and it is not that expensive. It is car toppable, easy set up and not that expensive. Check out the Wave forum too. You might find a used Wave. It is also easily set up by one and sailed by two. They are fun. I sailed one in the Bahamas with the whole family aboard.
On car topping though, even Sunfish sailors use a trailer these days. (Love your towing pic Jim
) I wish I had one of our H16 behind a Nissan Pulsar NX- the rig was about 3 times longer than the car
Trailing is easy, the boat is light. Stowage is another issue. It is just too big to put under the bed
You could just sail all year so you don't need to stow it.
Have fun and welcome to the world of blow-boats