This link is the Tein Flex Z thread and there is a few pictures in there. I have them and my pictures are on the last page.
The rear is maxed out and the front can go another half inch maybe. That is with the proper preload setting. If I mess with preload to lower I can another 1" in the rear. The front cannot mess with preload to lower but I can remove certain collars and other things to get it lower, maybe another 1/2" on top of that 1/2" spoke of earlier.
As for the Basis Z there is pictures all over this site but they have a similar height. I was trying to decided between the Basis Z and Flex Z also a while ago, went with the Flex Z because that was the long term goal, and the adjustability.
You can get one of them now as a way to get the car low for the show and then sell them when to get yourself a proper airbag setup. You would have no problem in selling them as long as you take care of them. This is the route that I may take as I want my car on bags if I ever widebody. This was just a thought as it is your money and life so I'm not here to control what you do.
With that, I would say that you would have to go with the Flex Z as you would need a separated spring perch and top hat. Seeing as the Basis Z use the stock top hat this wouldn't work. To truly see what would work and not work you should contact that company to see what you can do,
www.universalair.com. That is the company of the bags in the picture you posted.