Despite being reminded I still misread the OP's budget.... I'd spend the spare €1500 on a second sub.
I have, and love, QSC K12s (mk 1's) as well as Yamaha DXR10s. I prefer the sound of the QSCs but my thing is mostly acoustic and bluesy rock rather the heavier styles, the K12s suit acoustic styles very well. But, the Yamaha DZRs are the loudest in class and if I was buying again, and had the budget, they would get very serious consideration.
AlecSp wrote:How portable/compact does it need to be?
A Yamaha DZR/DXS solution would likely serve you very well.
At that budget, however, a used Nexo system could be in range, which would likely blow the socks of the Yamaha option. Then again, it's slightly different logistics as a Passive system. Either PS10 over LS500 or PS15 over LS1200.
A couple of cracking examples on ebay.co.uk at the moment. But I suspect you're not UK based, so your local experience may differ.
EUR 5000 is a good budget, and should get you a great system. But, as well as sounding great, its form factor needs to work for your logistis/transport. You really don't want to be spending that kind of money just on internet say so - make sure you get out and listen.
Th best sounding mid sized PA I've heard was a Nexo rig, truly exceptional. I believe Yamaha own Nexo.