Hi all, I have Cubase Pro 8 and I have tons of VSTs, my Pc is slow now. So I want to buy a very powerfull laptop (was even thinking about Mac Pro box) so I can carry it with me to a concert, training and at home. Could you advise best laptop for atleast 5 years to use it madlessly fast?! Cheers! 
I use these guys for my desktop DAW. They’ll build you a laptop designed to be a DAW instead of a general purpose machine (and without all the bloatware those have). They’ll even preload the software you already have licensed (up to a point). You can descuss with them how you intend to use it and they’ll advise you on the best confguration for your needs.
https://www.adkproaudio.com/laptops
I was in the same situation as you before with a powerful PC but lacked portability for the band and live shows. I then got a Macbook Pro 1TB + 2.8GHz and never looked back.
the only obvious downfall is the screen real estate and using the trackpad but u get use to it after a while!
for example in mac you can switch between the playlist and mixer (F3) with the swipe of 3 fingers (Virtual Desktop).