Curt, welcome to the forum. Getting in and out of the Crossfire, and how comfortable you are once you get there, depends mostly on age, hight, and weight.
I've never had the pleasure of driving a Z3, so I can't help you make a comparison. If you're tall, there's not much room to tilt the seat back. I'm 6'2", 210 lbs. so I had to get use to driving in a more upright position than I was normally accustomed to. But I adapted to it very quickly, and soon found it to be more comfortable and less strain on my neck.
Like you've been advised, driving one is all you need to do to be sure. If you fit, it's a very addictive place to be. Good Luck