4000 euros? Ah, you do realize that price is only for the professional edition with all the extras, right? It's unlikely that you'd need all those...
I think you'd be just fine with the Intro board to start with. Maybe you'd want a license for Live Pro too, if you do lots of shows to live bands or DJ's... But there's no need to get a pro board to start with unless you're planning to do laser shows for Walt Disney or something.
Most of the Pangolin LD-2000 users here on PL have nothing more than the Intro board.
Actually, if all you do are live shows, you might be better served with a Pangolin Flashback 3 system and a LivePro license. That combination is almost the same price as Mamba Black + the Medialas USB controller. But even if you did go for the LD-2000, the Intro board is only $1500... (Note that even an Intro board will still play back shows created using Pro-level features. The limit is only on new shows you create yourself.)
I have an intro board, and I love it. It's already able to do much more than I need right out of the box, and for certain it does lots more than Mamba Black can. I've had it for 2.5 years now, and I still haven't hit it's limits.
Granted, even an Intro board is still expensive. But at $1500 (or slightly less), it's a far cry from the 4000 euros you were thinking.
And along with the controller and all the software, you also get over 100 shows, plus tons of ILDA frames you can use to make your own shows. It's a hell of a good value, in my opinion. (And remember, I used to use Mamba!)
Anyway, it's something to keep in mind, should you ever think about upgrading in the future.
Adam