Why would you want to "drink coffee" in a Z4? It's a roadster and meant for driving. Heck, I never even turn my radio on. It sounds to me like you need to decide if you want a "sports car" or a "sporty car." There is a difference. The Mini is a great machine and a lot of fun to drive. I don't care for the ergonomics, myself, but that is a personal choice. The Zett 4 is the best sport scar I've ever owned. That said, I've never owned a Porsche or Ferrari, but I've had or driven just about every other non-exotic sport car out there in the past 30 years.
As always, buy the best car you can afford. Look for one with a service history. It will be obvious if it has been looked after. CPOs from the dealer are a good bet, but you will certainly pay more than for an older Z3. It depends on what you want the car to do and how much you want to spend. Decide those two things first and then go for what you want.
It's too bad we all just don't have piles of money, and then we could have all the cars we wanted and the garages to put them in. Good luck!
If you don't know where you are going, any road will get you there.